Poisoning of cattle with Gutierrezia microcephala, a perennial broomweed.


Rhabdomyosarcoma in the heart of a chicken.


Neurofibromatosis or von Recklinghausen's disease in a dog.


In vitro and in vivo tests of polymeric piperazine-1-carbodithioic acid as an equine boticide and anthelmintic.


African swine fever in wart hogs (Phacochoerus aethiopicus).


Clinical signs of blastomycosis in dogs.


The clinical management of snake venom poisoning in domestic animals.


Chloramphenicol and dihydrostreptomycin (chlorostrep) for treatment of diarrheas in dogs and cats.


The veterinary practitioner and nutrition.


THE EFFECT of malnutrition of viral infection.


Avian tuberculosis in mink; a case report.


Demodex folliculorum studies.  VI.  The internal phase of canine demodectic mange.


General anesthesia in birds.

General anesthesia in birds.


Intramedullary fixation of the chinchilla tibia.


A new technique for hernial repair in large animals.


Artificial insemination in swine.

Artificial insemination in swine.


Observations on radiodermatitis in horses.


Nutrition and Streptococcus agalactiae activity in milk.


The capacity of certain common laboratory animals to sweat.


Eversion of the lateral ventricles of the larynx in dogs; five cases.


Subconjunctival ablation of the eyeball of pet animals.


Chlorpromazine hydrochloride for the examination of the penis in bulls.


Results with newer therapeutic methods in large animal practice.  I.  Miscellaneous therapeutic measures.


Experimental investigations on current strains of hog cholera virus.


Results with newer therapeutic methods in large animal practice.  II.  The role of fluid and electrolyte therapy in lead arsenate poisoning.


Fluid therapy in the dog.

Fluid therapy in the dog.


Peritoneal lavage in uremia in dogs.

Peritoneal lavage in uremia in dogs.


Diagnosis and treatment of a dog with acinar atrophy of the pancreas.


Practical measurement of the pH of rumen fluid.


Alveolar dead space and arterial to end-tidal carbon dioxide differences during hypothermia in dog and man.


Effects of graded resistance to tracheal air flow in man.


Alveolar dead space as an index of distribution of blood flow in pulmonary capillaries.


Immediate effects of inhalation of 100% oxygen at one atmosphere on ventilation volume, carbon dioxide output, oxygen consumption and respiratory rate in man.


Evidence against the existence of specific ventilatory chemoreceptors in the legs.


Influence of local chemical change on ventilatory stimulus from the legs during exercise.


Work efficency and respiratory response of trained underwater swimmers using a modified self-contained underwater breathing apparatus.


Postoperative water and electrolyte changes in natives of high altitudes.


Use of the Pauling oxygen analyzer for measurement of oxygen consumption of animals in open-circuit systems and in a short-lag, closed-circuit apparatus.


Energy metabolism of the white rat after acclimation to warm and cold environments.


Diurnal oxygen consumption and rectal temperature of man during continuous cold exposure.


Peak oxygen uptake of healthy young men as determined by a treadmill method.


Countercurrent heat exchange and vascular bundles in sloths.


Changes in body weight and body dimensions in men performing work on a low calorie carbohydrate diet.


Effect of restricted water intake on urine nitrogen output in man on a low calorie diet devoid of protein.


Performance capacity and effects of caloric restriction with hard physical work on young men.


Steady and unsteady states of breath radon in subjects with chronic radium poisoning.


Force and work of digital arteriolar smooth muscle contraction in hypertension.


Clinical measurement of circulation time; a comparison of magnesium sulphate and Evans blue dye in normal subjects.


Vasomotor reactivity in Dupuytren's contracture.


Effect of methimazole on size of the heart in the rat.


Distensibility of blood vessels of the human calf determined by local application of subatmospheric pressures.


Hemodynamic measurements in experimental coronary shock.


Effects of magnesium sulfate on renal function, electrolyte excretion and clearance of magnesium.


Electrical activity of the human uterus in labor.


Hydrogen ion and hemoglobin concentration, carbon dioxide and oxygen content of blood of the pregnant ewe and fetal lamb.


Tensile and compressive strength of human parietal bone.


Motor responses of the esophagus to distention.


Relationship between sweat gland activity and electrical resistance of the skin.


Human erythrocyte ghosts prepared to contain various metabolites.


Tweens and a substrate for determination of the clearing factor.


Range and variability of measurements of venous pressure in man by direct manometry.


In-flight hyperventilation during jet pilot training.


The stress concept applied to flying.

The stress concept applied to flying.


Effects of high altitude exposure on dogs and on their susceptibility to endocarditis.


The physiology of pressure suits.

The physiology of pressure suits.


Subjective thermal comfort zones of ventilated full pressure suit at altitude.


An investigation of the effect of flying on speech intelligibility in noise.


Effects of mechanical force on living tissue.  III.  A compressed air catapult for high impact forces.


A device for artificial producation of alternating gravitational forces.


Audiometric studies of flight line mechanics.


Gaseous cavity formation in explosively decompressed animals.


Eye movement patterns in response to moving objects.


Investigations of the optimal characteristics of visual light indicator systems.


Control knob arrangement can save aircraft instrument panel space.


A set of radiumneedles and tubes especially designed for use with the Paterson-Parker-system.


Deoxyribonucleases of mouse tissues.

Deoxyribonucleases of mouse tissues.


Radium implant time charts.

Radium implant time charts.


The biosynthesis of histidine; L-histidinol phosphate phosphatase.


A comparison of the reaction kinetics of adenylic acid and adenosine diphosphate with the respiratory chain.


The effect of thyroxine on magnesium requirement.


Pyridine coenzymes of subcellular tissue fractions.


The biosynthesis of fatty acids in rat liver.


The conversion of 5-methyldeoxycytidine to thymidine in vitro and in vivo.


Influence of adrenocorticotropic hormone on corticoid production and glycine-1-C14 incorporation into protein by rat adrenals.


Pantothenylcysteine, a precursor of pantetheine in Lactobacillus helveticus.


The cleavage of alpha-methylserine and alpha-methylolserine by pyridoxal and metal ions.


Biosynthesis of itaconic acid in Aspergillus terreus.  I.  Tracer studies with C14-labeled substrates.


Bile acids.  VI.  The structure and synthesis of acid II.


Biosynthesis of itaconic acid in Aspergillus terreus.  III.  The properties and reaction mechanism of cis-aconitic acid decarboxylase.


Biosynthesis of itaconic acid in Aspergillus terreus.  II.  Early stages in glucose dissimilation and the role of citrate.


Metabolism of 21-deoxyhydrocortisone-4-C14 in man; 17-dehydroxylation, an artifact.


The incorporation of S35-sulfate into heparin.


Serine metabolism in rat liver slices.

Serine metabolism in rat liver slices.


Effect of ethylenediaminetetraacetic acid on deposition and excretion of certain rare earth elements.


The wheat leaf phosphatases.  III.  A survey of the heat stability of the enzymes active at pH 5.7.


Observations on the function of cytochromes c and c1.


The microestimation, distribution, and biosynthesis of 2, 3-diphosphoglyceric acid.


Studies on the fixation of radioselenium in proteins.


Nicotinic acid metabolism.  III.  C14-carboxyl-labeled nicotinamide and nicotinic acid in the chick.


An enzyme-catalyzed acyl migration; a lysolecithin migratase.


The effect of antibiotics upon intestinal and hepatic lipogenesis.


The synthesis and biological properties of fatty acyl adenylates.


Pathway of noradrenaline formation from DOPA.


Inactivation of lipoprotein lipase by heparinase.


Lipoprotein lipase of chicken adipose tissue.


The degradation of heparin by bacterial enzymes.  III.  A comparison of the degradation of heparin, hyaluronic acid, and chondroitin sulfate.


The nature of the lipides in rat blood.

The nature of the lipides in rat blood.


The formation of radioactive lycopene in ripening tomatoes.


On the biosynthetic relationship between lycopene and colorless polyenes in tomatoes.


The pH dependence and dissociation constants of esterases and proteases treated with diisopropyl fluorophosphate.


The synthesis and metabolism of enantiomorphic forms of glycerol-1-C14.


The reactivity of esterases and proteases in the presence of organophosphorus compounds.


Pathways of glycerol dissimilation in two strains of Aerobacter aerogenes; enzymatic and tracer studies.


Studies on the mechanism of action of azathymine.  III.  Relationship between incorporation into deoxypentose nucleic acid and inhibition.


Distribution of metals in subcellular fractions of rat liver.


On the conversion of squalene to lanosterol in vitro.


On the mechanism of enzymatic cyclization of squalene.


On the demethylation of lanosterol to cholesterol.


Modification of human serum lipoprotein fractions by lipide extraction.


The preparation of isocitric dehydrogenase from mammalian heart.


The enzymatic properties of isocitric dehydrogenase.


Pyrazolopyrimidines as inhibitors and substrates of xanthine oxidase.


The biosynthesis of nucleic acid ribose and of glycogen glucose in the rat.


Lactose synthesis.  II.  The distribution of C14 in lactose of milk from the perfused isolated cow udder.


Lactose synthesis.  I.  The distribution of C14 in lactose of milk after intravenous injection of C14 compounds.


Studies on the action of thymidine analogues.


On the mechanism of the aconitase and isocitric dehydrogenase reactions.


Nucleotide specificity of oxalacetic carboxylase.


Reversible synthesis of polyribonucleotides with an enzyme from Escherichia coli.


Conversion of uracil and orotate to uridine 5'-phosphate by enzymes in lactobacilli.


The fine structure of nuclei during sperm maturation in the locust. 1. In the heads of maturing sperm of a locust the chromatin becomes arranged in a highly regular manner so as to produce many parallel lines about 60 A thick in longitudinal section and contiguous polygons in transverse section. 2. This configuration appears after fixation in osmium tetroxide, formaldehyde, or acetic acid; intermediate stages in its development are illustrated. 3. These electron micrographs are interpreted to mean that, during sperm maturation, the chromatin becomes formed into sheets and then into tubes running parallel with the long axis. 4. In the mature sperm head we have been unable so far to detect this structure. This may be because the chromatin becomes so compact during the shrinkage of the nucleus which occurs during formation of the mature sperm.


The nutrition of animal tissues cultivated in vitro.  IV.  Amino acid requirements of chick embryonic heart fibroblasts. 1. The amino acid requirements of freshly explanted chick embryonic heart tissues cultivated in completely synthetic media have been determined, employing a nutritional depletion technique. Arginine, histidine, lysine, tyrosine, tryptophan, phenylalanine, cystine, methionine, threonine, leucine, and valine were found to be essential. Serine, isoleucine, glycine, and glutamine were found to be non-essential. Glutamic acid, aspartic acid, alpha-alanine, proline, and hydroxyproline were found to be inhibitory in this test system. 2. A total amino acid level of approximately 100 mg. per cent was found to be optimal and DL-amino acids were found to be non-toxic, unless used in high concentrations. 3. A comparison has been made of the amino acid requirements of various types of tissue cultures, of the chick, and of man and certain differences in these requirements have been discussed.


An electron microscope study of the morphology and distribution of the intracytoplasmic virus-like particles of Ehrlich ascites tumor cells. Electron microscope studies of eight different sublines of Ehrlich ascites tumor cells which had not, as far as could be determined, come in contact with any known virus, revealed dense particles measuring approximately 55 to 70 mmicro in diameter, both within and attached to the wall of cytoplasmic vesicles identified as the endoplasmic reticulum. All tumor sublines contained significant numbers of particles and revealed no qualitative or quantitative differences in particle morphology or distribution. It is concluded that these structures are a constant morphological component of the Ehrlich ascites tumor and that they probably do not represent contaminating virus. Their morphology and distribution are described, and the possible interpretations of their significance are discussed.


Some aspects of the metabolism of sulfate-S35 and calcium-45 in the metaphyses of immature rats:  influence of beta-estradiol benzoate. Weanling rats were given 2 mg. of 17-beta-estradiol benzoate at weekly intervals for 4 weeks. Twenty-four hours after each intraperitoneal injection of the estrogen 100 microc. of S(35)-sulfate or 11 microc. of Ca(45) was similarly injected. The animals were sacrificed 24 hours after the last dose of isotopes. An effect of estradiol benzoate on calcium metabolism was deduced from the observation that the concentration of calcium in some tissues of the treated rats was higher than the concentration in the tissues of untreated rats. Alkaline extracts of the distal metaphyses of femurs from the estradiol-treated and from control rats, given S(35)-sulfate, were shown by chromatography on an anion exchange resin to contain from 9 to 22 per cent of the S(35) as inorganic sulfate. From similar bone samples, 6 to 21 per cent of the S(35) was removed by decalcification with sodium versenate. Most of the remaining S(35) was associated with uronic acid and hexosamine; on paper chromatograms and paper electrophoretograms S(35) was shown to be part of material which migrated and was metachromatic in the same way as purified chondroitin sulfate. Autoradiograms of the proximal ends of tibiae from the animals given estradiol benzoate showed that both the S(35) and Ca(45) were deposited in the metaphyses in strata. The arrangement of the strata of S(35), however, was different from the arrangement of the strata of Ca(45). This difference in arrangement is interpreted as indicating that most of the S(35) in the metaphysis was derived from the chondroitin sulfate of the cartilage plate which the metaphysis had replaced.


The structure of the primary epidermal cell wall of Avena coleoptiles. The primary walls of epidermal cells in Avena coleoptiles ranging in length from 2 to 40 mm. have been studied in the electron and polarizing microscopes and by the low-angle scattering of x-rays. The outer walls of these cells are composed of multiple layers of cellulose microfibrils oriented longitudinally; initially the number of layers is between 10 and 15 but this increases to about 25 in older tissue. Where epidermal cells touch, these multiple layers fuse gradually into a primary wall of the normal type between cells. In these radial walls, the microfibrils are oriented transversely. Possible mechanisms for the growth of the multilayered outer wall during cell elongation are discussed.


An electron microscope study of the embryology of the intercalated disc in the heart of the rabbit. Prenatal and postnatal cardiac muscle from rabbits has been studied by electron microscopy, after osmium fixation and methacrylate embedding. The observations showed that 1. Cell membranes divide the muscle into cellular units from the youngest embryo which was studied (9(1/2) days after coitus) until the adult state. 2. The embryonic muscle cells contain only one nucleus, whereas the adult cell may be multinucleated. 3. At all stages of development, wherever a myofibrillar axis crosses a cellular boundary, the myofilaments are interrupted by an intercalated disc. 4. With age, increase in size and complexity of the discs render them recognisable by the light microscope.


Electron microscopy of the avian renal glomerulus. Electron microscopy of sections of chicken glomeruli shows them to possess a large central cell mass, occupying the hilum and the centre of the glomerulus, and continuous with the adventitia of the afferent and efferent arterioles. The glomerular capillaries form a much simpler system than in mammals and are spread over the surface of the central cell mass. Between the capillaries the mass is limited externally by the major component of the glomerular capillary basement membrane, which continues over the surface of the mass from one capillary to the next. Projections of the central cell mass characteristically form the support for glomerular capillaries, and smaller knobs of the central mass may project actually into the lumen of the capillaries, but always carry a layer of endothelial cytoplasm before them. They are never in direct contact with blood. The basement membrane of the glomerular capillary loop has a central dense layer and two lateral less dense layers as in mammals. The central dense layer is continuous with similar appearing dense material in the intercellular spaces of the adventitiae of the arterioles, and also with that of the central cell mass. The two less dense layers can also be traced into direct continuity with the less dense regions of this intercellular substance. The endothelial cytoplasm is spread as a thin sheet over the inner surface of the capillary basement membrane, and shows scattered "pores" resembling those described in mammals. Epithelial cells with interlacing pedicels are at least as prominent as those in mammals. Bowman's capsular membrane also possesses three layers similar to but less wide than those of the capillary basement membrane, and all three layers can be traced into continuity with the dark and light regions of the intercellular material of the adventitial cells of the arterioles, and beyond them with that of the central cell mass. At the hilum Bowman's capsular membrane also fuses with the capillary basement membrane.


The electron microscopy of the human hair follicle.  I.  Introduction and the hair cortex. 1. The presumptive cortical cells of hair in the undifferentiated matrix of the bulb contain mitochondria, agranular vesicles, and many small dense R.N.P. particles, but no keratin, pigment granules, or endoplasmic reticulum. 2. In the mid-bulb region intercellular adhesion is limited to small localised areas. Intercellular gaps are common and the cell surfaces are irregularly convoluted. The melanocyte processes penetrate the cell gaps. The relation between their pigment-bearing tips and the involutions of the cell membranes suggests an active phagocytosis of the tips. 3. Fibrous keratin first appears in loose parallel strands of fine filaments (ca. 60 A diameter) in the mid-bulb. The filaments, the long mitochondria, and elongated nucleus are all parallel to the long axis of the cell and the axis of the follicle. 4. At the level of the constriction of the bulb and above, a dense amorphous substance appears between the fine filaments and apparently acts as adhesive cement. The bundles of filaments now form well defined fibrils. The packing of the filaments within the fibrils is in places hexagonal and elsewhere in the form of "whorls." 5. At higher levels further filaments and interfilamentous cement are added together and the whole cytoplasmic space becomes packed with fibrils which finally condense to massive blocks of keratin. The residual cellular material occupies the interstices. 6. The addition of the interfilamentous substance is regarded as an essential factor in keratinisation. Keratin is considered to be a complex made of fine filaments (alpha-filaments) embedded in an amorphous substance (gamma-keratin) which has the higher cystine content. 7. The wide-angle fibre-type x-ray pattern is thought to be due to scattering by the fine alpha-filaments and some low angle lateral spacings to the filament-plus-cement structure.


The electron microscopy of the human hair follicle.  II.  The hair cuticle. 1. During the early differentiation of the cuticle the cell membranes smooth out and the cells become closely attached over most of their surface. The change seems to be due to a layer of cement which forms between them. The plasma membranes also increase in density. 2. The decreased membrane activity of the cuticle cells may prevent a phagocytosis of the melanocyte processes and thus account for the non-pigmentation of the cuticle. 3. The flattening and imbrication of the cuticle may possibly be explained by a zipper-like spread of cell contacts. 4. Keratinisation of the cuticle occurs at a late stage in its development; the keratin formed is an amorphous type, similar to the gamma-fraction of the cortex which is produced at a similar level. 5. Keratinisation is accompanied by the formation of complex intercellular layers similar to structures observed in the inner root sheath (see Part 3). 6. In the final stage of keratinisation the remaining cytoplasm condenses with the result that the cell is divided into a laminated structure with an outer keratinised layer and an inner layer, which is insoluble in keratinolytic solvents.


The electron microscopy of the human hair follicle.  III.  The inner root sheath and trichohyaline. 1. The three cylinders of cells, each one cell thick, which together constitute the inner root sheath, arise from the peripheral portions of the undifferentiated matrix. These cells, like the hair cuticle, are stabilised by the spread of adhesive contacts between their plasma membranes which occurs in the mid-bulb and upper bulb of the hair follicle. 2. The characteristic intracellular product of all three cell layers is trichohyaline. This substance is formed in the first place as amorphous droplets which subsequently transform into a birefringent form. 3. This transformation, involving the formation of a birefringent product from an amorphous precursor, is in contrast to the formation in the cortex of keratin which originates in a fibrous form. 4. Trichohyaline appears first and transforms first in the cells of Henle which are nearest the outer sheath and the dermal supply vessels. This transformation occurs at the level of the neck of the follicle. Synthesis and transformation in the cells of Huxley and the sheath cuticle lag behind the similar events in the cells of Henle. The transformation does not begin until the lower prekeratinous zone in the Huxley and cuticle cells. 5. The amorpous-fibrous transformation occurs rapidly cell by cell and involves the conversion of all the trichohyaline droplets. In longitudinal sections the birefringent modification can be seen extending from the droplets in both directions parallel to the axis of the hair. In cross-sections the images of the transformed material are difficult to interpret. They may be seen as sections of corrugated sheets ( approximately 100 A thick) or condensed fibrils approximately 100 A in width. 6. At the same time that the trichohyaline transforms, the spacing between the cell membranes increases and a dark deposit appears centrally between them. This membrane complex, and the similar complex of the hair cuticle cells described in Part 2, may be specialised formations whose purpose is to hold the hardened cells together.


Autoradiographic studies of the utilization of S35-sulfate by the chick embryo. From studies of autoradiograms of various developmental stages of the chick embryo containing S(35) given us sulfate it was determined that as early as Stages 3+ and 4 there is a selective utilization or accumulation of sulfate by the various parts. The earliest accumulation site is the axial portion of the primitive streak and the floor of the groove. Later S(35) was found in the head process, Hensen's node, notochord, amniocardiac vesicle, wall of the omphalomesenteric vein, endocardium, subendocardial jelly, mesenchyme destined to become cartilage, basement membrane area of the gut, and a mucopolysaccharide layer formed on the free surface of the stomach. The early notochordal localizations of S(35) coincide with the region in which a thin ring of chondroitin sulfate is subsequently laid down. However, it is apparent that there is an intracellular accumulation of inorganic sulfate by the chondroitin-forming cells prior to the time they produce sufficient chondroitin sulfate to be demonstrable histochemically. It was interesting to note that the endocardium appears to concentrate sulfate that later apparently finds its way into the subendocardial jelly. The fact that those mesenchymal cells which later form chondroblasts begin to utilize sulfate selectively before histological differentiation is apparent was determined. In addition, the presence of sulfate-containing substances in the forming basement membrane of the gut would seem to indicate that sulfate is important in the histological differentiation of this membrane.


Effect of gamma irradiation on the desoxyribonuclease II activity of isolated mitochondria. 1. Exposure of isolated liver mitochondria to high doses of gamma rays from a Co(60) source causes the level of DNase II activity to increase. Treatment of the mitochondria with sonic vibration causes a further elevation of the activity to a level which is independent of the prior radiation dose. 2. Such increased mitochondrial DNase II activity appears to be due to the "structural damage" of the subcellular particulates caused by the ionizing radiation. Other methods of disrupting the mitochondrial structure also cause increased DNase II activity. A causal relationship between the structural alteration and the increased enzymatic activity is postulated. 3. The DNase II activity appears to be closely associated with the structural elements of the mitochondria and remains associated with the fragments after irradiation. 4. Upon irradiation, the mitochondrial suspension releases ultraviolet-absorbing materials which are probably nucleotide in nature. 5. The possibility of localization of DNase activity in the lysosome fraction of de Duve (15) is discussed. It is felt that DNase II is at least in part a mitochondrial enzyme and that probably the conclusions drawn here would be applicable to any DNase II present in the lysosomes as well. 6. Irradiation of whole liver homogenate causes no increased DNase II activity. The experiments do not provide any information on the presence or action of protective substances in the homogenate.


The base of the proximal convoluted tubule cells of rat kidney. The three dimensional arrangement of the compartments on the base of proximal convoluted tubule cells of rat kidney is described. An extracellular basal labyrinth is found to be enclosed by these compartments. The compartments with their mitochondria and the basal labyrinth are regarded as forming a functional unit. It is supposed that this basal unit serves for excretion of reabsorbed fluid from the cell into the labyrinth and for the development of hydrostatic pressure in the labyrinth to overcome the capillary pressure and to pass the reabsorbed fluid into the blood stream.


Electron microscope study of mammalian cardiac muscle cells. The cellular theory of heart muscle is supported by a detailed description of the intercalary discs. The discs are adjacent plasma membranes separated by an interspace while the sarcolemma appears as plasma membrane, interspace plus basement membrane of the interstitium. The nucleus of the cell is closely associated with the entire cell by way of the endoplasmic reticulum. Transversely it connects the outer nuclear membrane at the level of the Z and M bands with the contractile material and the sarcolemma. Longitudinally it connects the outer nuclear membrane with the plasmalemma at the intercalated discs. The description of the spiral attachment of the endoplasmic reticulum on the outer nuclear membrane supplements earlier observations on the helicoidal structure of the heart muscle cell. Plasma membranes and endoplasmic reticulum are considered to be carriers of membrane potentials and to conduct excitation.


Electron microscope study of the vitelline body of some spider oocytes. THE STRUCTURE OF THE VITELLINE NUCLEI OF LYCOSIDAE AND THOMISIDAE WAS DESCRIBED AS FOLLOWS: Vitelline nuclei are constituted of two parts: (a) a peripheral layer (vitelline body cortex), and (b) a central core. The vitelline body cortex is demonstrated to be formed by many cisternae of the endoplasmic reticulum among which mitochondria and Golgi elements are intermingled. The central core is made up mainly of a special type of body described under the name of "capsulated body." Capsulated bodies comprise a capsular layer, limited by a membrane, and two central masses called "geminated masses," each one limited by a double membrane. Irregular masses of closely packed vesicles are found in some cases among the capsulated bodies and free vesicles are present in large numbers. The optical properties of the vitelline body cortex compared with the electron microscope findings lead us to the concept that this layer is a "composite body" according to Weiner's theory.


Studies on the endoplasmic reticulum.  III.  Its form and distribution in striated muscle cells. Several types of striated muscle have been examined by the technics of electron microscopy and the findings in myotome fibers of Amblystoma larvae, the sartorius, and cardiac muscle of the rat are reported on in some detail. Particular attention has been given to structural components of the interfibrillar sarcoplasm and most especially to a finely divided, vacuolar system known as the sarcoplasmic reticulum. This consists of membrane-limited vesicles, tubules, and cisternae associated in a continuous reticular structure which forms lace-like sleeves around the myofibrils. It shows a definable organization which repeats with each sarcomere of the fiber so that the entire system is segmented in phase with the striations of the associated myofibrils. Details of these repetitive patterns are presented diagrammatically in Text-figs. 1, 2, and 3 on pages 279, 283, and 288 respectively. The system is continuous across the fiber at the H band level and largely discontinuous longitudinally because of interruptions in the structure at the I and Z band levels. The structure of the system relates it to the endoplasmic reticulum of other cell types. The precise morphological relation of the reticulum to the myofibrils, with specializations opposite the different bands, prompts the supposition that the system is functionally important in muscle contraction. In this regard it is proposed that the membrane limiting the system is polarized like the sarcolemma and that the corresponding potential difference is utilized in the intracellular distribution of the excitatory impulse.


Thin sectioning:  details of techniques.

Thin sectioning:  details of techniques.


Re-utilization of lymphocytes in lymphopoiesis.


Electron microscopic evidence suggesting secretory granule formation within the Golgi apparatus. Secretory granules have been seen within components of the Golgi bodies of rat pituitary acidophils and mouse pancreatic acinar cells. The fact that secretory granules are much more frequently encountered within Golgi components under conditions of increased secretory activity suggests that granule formation may occur within the Golgi apparatus in these two types of cells.


The occurrence of intranuclear crystals in living HeLa cells infected with adenoviruses.


Problems in methacrylate embedding for electron microscopy.


A cytological study of the albuminsecreting cells of the hen oviduct. 1. The electron and light microscope have been employed in a cytological study of the albumin-secreting cells of the hen oviduct and of fractions of this tissue obtained after homogenization and differential centrifugation. 2. These studies confirm the observation that in this tissue material corresponding to liver "microsomes" in amino acid-incorporating ability and ribonucleic acid content sediments in relatively low centrifugal fields. 3. The electron microscope studies suggest that the protein secretion of the gland is formed in intimate association with the ergastoplasm.


Electron microscopy of the pacinian corpuscle. The Pacinian corpuscle has a framework of cytoplasmic lamellae arranged concentrically in the outer zone, and bilaterally in the core. Between these is an intermediate growth zone. The inner core shows an unexpected complexity in that its component lamellae are arranged in two symmetrical groups of nested cytoplasmic sheets. Longitudinal tissue spaces form clefts separating the two groups. The perikarya of the core lamellae lie in or near the intermediate growth zone, and send arms into the clefts. The arms then branch and terminate as lamellae which interdigitate with those of neighboring cells. The single nerve fiber loses its myelin sheath just before it reaches the inner core but retains its Schwann cell cytoplasmic covering for a short additional distance. The Schwann sheath is not continuous with the lamellae of the inner core. Inside the core the fiber contains a striking circumferential palisade of radially disposed mitochondria. The fiber does not arborize. Vascular capillaries penetrate the hilar region of the corpuscle only as far as the myelinated sheath of the nerve, and they have not been seen elsewhere in the corpuscle. There is direct continuity between the clefts of the core and tissue spaces in the vicinity of the capillaries. It is likely that this provides a route whereby metabolites reach the active nerve ending, as well as the cells of the growth zone. The outer zone consists of at least 30 flattened concentric cytoplasmic lamellae separated from one another by relatively wide fluid-filled spaces. Collagenous fibrils are present, particularly on the outer surface of lamellae, and tend to be oriented circularly. The girdle of proliferating cells constituting the growth zone, which is prominent in corpuscles from young animals, is the layer from which the outer lamellae are derived. Osmotic forces probably elevate the lamellae, and maintain turgor pressure.


Histology and cytochemistry of human skin.  XI.  The distribution of beta-glucuronidase. 1. Various amounts of beta-glucuronidase activity may be found in all of the cutaneous appendages. 2. In the epidermis, the basal layer and the Malpighian layer contain a moderate amount of it, but a band of cells, including the stratum granulosum and the cells immediately above it, is rich in beta-glucuronidase. 3. The cells of the duct of eccrine sweat glands have moderately strong enzyme activity, but those in the secretory coil are strongly reactive; small and large reactive granules are crowded in the reactive cytoplasm. 4. The cells of the secretory coil of the apocrine glands contain more beta-glucuronidase than any other cutaneous appendage. 5. In the sebaceous glands, a very strong concentration of enzyme activity is found in the undifferentiated peripheral cells, a smaller amount of it is found in the differentiating cells. 6. In active hair follicles, the largest amount of beta-glucuronidase is found in the outer root sheath and in the bulb. In the outer sheath, the strongest concentration is found around the level of the keratogenous zone of the cortex. The dermal papilla is strongly reactive. In quiescent hair follicles, the outer root sheath has a moderate amount of enzyme concentration, but the dermal papilla is unreactive. 7. In the dermis, the fibroblasts in the papillary layer, the smooth muscle cells of the arrectores pilorum and the tunica media of arteries, and the fat cells all exhibit enzyme activity. Mast cells show a great concentration of beta-glucuronidase.


Cellular differentiation in the kidneys of newborn mice studies with the electron microscope. The structure of the kidney of the Swiss albino mouse changes progressively during the first 2 weeks after birth. Cells proliferate to form new nephrons, cells differentiate by acquiring specialized membranous components, and certain cytological features which are present at birth diminish in abundance or disappear. The differentiation of the cells of the cortical tubules has been studied using the light and electron microscopes. The tubules are partially and variably differentiated at birth. During the first 2 weeks after birth the brush border develops in the proximal tubules by the accumulation of numerous microvilli on the apical cell margins. Basal striations develop in proximal and distal tubules as an alignment of mitochondria, the result of what appears to be progressive interlocking of adjacent fluted cells. The mitochondria increase in number and size, accumulate homogeneous matrix, and acquire small, very dense granules. The collecting ducts develop tight pleating of the basal cell membranes, and dark cells containing numerous small cytoplasmic vesicles and microvilli appear. At birth there are dense irregular cytoplasmic inclusions presumed to be lipide in renal cells, the cytoplasmic granules of Palade are abundant, and there are large round bodies in the cells of the proximal tubules. The lipide inclusions disappear a few days after birth, and the cytoplasmic granules of Palade diminish in abundance as the cells differentiate. The large round bodies in the proximal tubules consist of an amorphous material and contain concentrically lamellar structures and mitochondria. They resemble the cytoplasmic droplets produced in the proximal tubules of adult rats and mice by the administration of proteins. The large round bodies disappear from the proximal tubules of infant mice during the first week after birth, but the concentric lamellar structures may be found in adult mice.


Experimentally induced chromosome abberrations in plants.  II.  The effect of cyanide and other heavy metal complexing agents on the production of chromosome aberrations by x-rays. The discovery of Lilly and Thoday, that the presence of potassium cyanide (KCN) increases the production of chromosome aberrations by x-rays in anoxia, but has no effect on the production of chromosome aberrations by x-rays in air, was confirmed. In the presence of cyanide, the effect of a given dose of x-rays in nitrogen was found to be even greater than the effect of the same dose of x-rays in air. The cyanide effect on x-ray breakage in nitrogen was obtained at cyanide concentrations as low as 2 x 10(-5)M. The breakage obtained after the combined x-ray-cyanide treatments was of the x-ray type, as evidenced by the distribution of breaks within and between the chromosomes. A number of other heavy metal complexing agents as well as some other compounds were tested for their ability to increase x-ray breakage in nitrogen and air. Of these compounds only cupferron proved to be effective. The results are discussed and it is concluded that the increased x-ray breakage in the presence of cyanide or cupferron cannot be due to an accumulation of peroxides. Instead it is suggested that the cyanide effect may be due to a complex formation between the active agents and heavy metals, presumably iron, within the chromosomes. The consequences of this hypothesis on the concept of the "oxygen effect," are discussed.


Experimentally induced chromosome aberrations in plants.  I.  The production of chromosome aberrations by cyanide and other heavy metal complexing agents. The finding of Lilly and Thoday that potassium cyanide produces structural chromosome changes in root tips of Vicia faba was confirmed. Like mustards, diepoxides, and maleic hydrazide, potassium cyanide seems to act on cells at early interphase. A tendency of cyanide breaks to be concentrated in heterochromatic segments of the chromosomes was evident. The production of chromosome aberrations by cyanide proved to be practically unaffected by the temperature during treatment. In agreement with Lilly and Thoday, the effect of potassium cyanide was found to be dependent on oxygen tension during treatment. The effect of potassium cyanide increases with increasing oxygen concentration up to 100 per cent oxygen. In the absence of oxygen, potassium cyanide was not completely inactive, but produced a low, though significant frequency of aberrations. Pretreatments with 2.4-dinitrophenol did not influence the effect of potassium cyanide. When bean roots were treated with potassium cyanide before a treatment with 8-ethoxycaffeine, or at the same time as they were treated with 8-ethoxycaffeine, the effect of 8-ethoxycaffeine was almost completely suppressed. The effects of a number of other heavy metal complexing agents were also tested. Sodium fluoride, potassium thiocyanate, carbon monoxide, o-phenanthroline, 2.2-bipyridine, and sodium azide were without radiomimetic effect under the conditions employed, and so was a mixture of sodium azide and sodium fluoride. A low, but quite significant, radiomimetic effect was obtained after treatments with sodium diethyldithiocarbamate, cupferron, and 8-hydroxyquinoline. Under anaerobic conditions, the effects of cyanide and cupferron were both quantitatively and qualitatively indistinguishable. Unlike the effect of cyanide, the effect of cupferron was not enhanced by the presence of oxygen. The effects of the same heavy metal complexing agents were tested on the activities of the enzymes catalase and peroxidase. The activities of both of these enzymes were found to be totally inhibited only by potassium cyanide. In the other cases, little correlation was found between ability to inhibit the activities of these enzymes and ability to produce chromosome aberrations. In a number of experiments, hydrogen peroxide was found to be without radiomimetic effect, whether alone or in combination with potassium cyanide. t-Butyl hydroperoxide proved to be active. The effect of t-butyl hydroperoxide was substantially increased by pretreatments with 2.4.-dinitrophenol. The results are discussed, and it is concluded that the observations made do not support the hypothesis that hydrogen peroxide is involved in the production of chromosome aberrations by potassium cyanide. The possibility that organic peroxides are involved cannot be excluded on the bases of the experimental results. As an alternative hypothesis, it is suggested that iron or other heavy metals are present in the chromosomes and that cyanide and other heavy metal complexing agents produce chromosome aberrations by reacting with these metals.


The form birefringence of lamellar systems containing three or more components.


Mucopolysaccharides produced in tissue culture. 1. A method of mass tissue culture has been devised by which, in a relatively short period of time, samples large enough for chemical isolation of mucopolysaccharides can be obtained. 2. Chemical isolation of acid mucopolysaccharides from mass cultures of human fetal skin, human fetal bone, bovine fetal skin, and rat subcutaneous tissue has been carried out. It has been found that the fibroblasts of each of these tissues produce in tissue culture more than one mucopolysaccharide, namely, hyaluronic acid, and a chondroitin sulfate. 3. The chondroitin sulfate produced by fibroblasts of the above tissues in tissue culture was not fully sulfated. The possible significance of this finding is discussed.


Intracellular localization of enzymes in spleen.  I.  Reduced diphosphopyridine nucleotide cytochrome c reductase, cytochrome c oxidase, and succinic dehydrogenase in the rat and guinea pig. 1. The intracellular distribution of nitrogen, DPNH cytochrome c reductase, succinic dehydrogenase, and cytochrome c oxidase has been studied in fractions derived by differential centrifugation from rat and guinea pig spleen homogenates. 2. In the spleens of each species, the nuclear fraction accounted for 40 to 50 per cent of the total nitrogen content of the homogenate, and the mitochondrial, microsome, and supernatant fractions contained about 8, 12, and 30 per cent of the total nitrogen, respectively. 3. Per mg. of nitrogen, DPNH cytochrome c reductase was concentrated in the mitochondria and microsomes of both rat and guinea pig spleens. Seventy per cent of the total DPNH cytochrome c reductase activity was recovered in these two fractions. The reductase activity associated with the nuclear fraction was lowered markedly by isolating nuclei from rat spleens with the sucrose-CaCl(2) layering technique. The lowered activity was accompanied by the recovery of about 90 per cent of the homogenate DNA in the isolated nuclei, indicating that little, if any, of the reductase is present in spleen cell nuclei. 4. Per mg. of nitrogen, succinic dehydrogenase was concentrated about 10-fold in the mitochondria of rat spleen, and 65 per cent of the total activity was recovered in this fraction. 5. Cytochrome c oxidase was concentrated, per mg. of nitrogen, in the mitochondria of both rat and guinea pig spleens. The activity associated with the nuclear fraction was greatly diminished when this fraction was isolated from rat spleens by the sucrose-CaCl(2) layering technique. Only 50 to 70 per cent of the total cytochrome c oxidase activity of the original homogenates was recovered among the four fractions from both rat and guinea pig spleens, while the specific activities of reconstructed homogenates were only 55 to 75 per cent of those of the original whole homogenates. This was in contrast to the results with DPNH cytochrome c reductase and succinic dehydrogenase where the recovery of total enzyme activity approached 100 per cent, and the specific activities of reconstructed homogenates equalled those of the original homogenates. The recovery of cytochrome c oxidase was greatly improved when only the nuclei were separated from rat spleen homogenates. 6. Data were presented comparing the concentrations (ratio of activity per mg. of nitrogen of the fraction to activity per mg. of nitrogen of the homogenate) of DPNH cytochrome c reductase in mitochondria and microsomes derived from different organs of different animals. 7. Data were presented comparing the activities per mg. of nitrogen of DPNH cytochrome c reductase in homogenates from several organs of various animals.


Morphology of the ommatidia of the compound eye of Limulus. The sensory portion of the ommatidium of the compound eye of Limulus has been studied with the electron microscope. In axial longitudinal section the rhabdom appears to be made up of small polygons, and in transverse section the rhabdom appears as a banded structure of dark lines. Thus in three dimensions the rhabdom resembles a honeycomb composed of tubular units, the long axes of which lie in transverse planes and are oriented perpendicular to the retinula cell's contours. The tubular units, which are about 140 mmicro in diameter in Limulus (70 mmicro in diameter in the spider and Scutigera), are microvilli of the borders of the retinula cells. The walls of these microvilli are continuous with fine linear structures (membranes) in the cytoplasm of the retinula cells. In transverse sections of the ommatidium oval bodies interpreted as mitochondria are observed in an annular zone at the tips of the rhabdom's rays. These mitochondria, which are 2 to 10 micro in diameter, are crowded with irregular closed outlines about 100 mmicro in diameter. Possible functions of components of the ommatidium are discussed.


The microstructure of the compound eyes of insects. The apposition eyes of two diurnal insects, Sarcophaga bullata (Diptera) and Anax junius (Odonata), have been examined with the electron microscope. In the latter case only the rhabdom is described. The rhabdom of the fly consists of a central matrix and seven rhabdomeres, one for each retinula cell. The rhabdomeres show an ordered internal structure built up of transverse tubes, hexagonal in cross-section. These slender compartments running the width of the rhabdomere are 370 A in diameter. After fixation with osmium tetroxide the walls of the compartments are more electron dense than the interiors. The retinula cells contain mitochondria, and pigment granules smaller than those found in the pigment cells. These granules tend to cluster close behind the membranes which separate the retinula cells from their rhabdomeres. The rhabdom of the dragonfly is a single structure which appears to be composed of three fused "rhabdomeres," each similar to a rhabdomere of Sarcophaga. Reasons are given for believing that the rhabdom may be the site of photoreception, as well as the organ for analyzing plane-polarized light, as suggested by other workers.


Photoreceptor structures.  III.  Drosophila melanogaster. The eyes of three eye mutants of Drosophila melanogaster were fixed and thin sections studied for its structural detail in the electron microscope. Each ommatidium was found to have seven retinula cells with an equal number of rhabdomeres (visual units). The rhabdomeres average 1.2 micro in diameter and 60 micro in length. Each rhabdomere consists of osmium-fixed dense bands averaging 120 A in thickness, and with less dense interspaces 200 to 400 A. There is an average of 23 dense bands or 46 interfaces per micron within the rhabdomere. The rhabdomere as we have presented it is a single structure of packed rods or tubes. The "fine structure" within the rhabdomere is similar to that observed by electron microscopy for the retinula of the house fly, and to the retinal rods of the vertebrate eye, and to the chloroplasts of plant cells in a variety of animal and plant photoreceptor structures. In addition, the radial arrangements within the ommatidium of radially unsymmetrical units, the rhabdomeres, is probably related to the analysis of polarized light in the insect eye.


The Nissl substance of living and fixed spinal ganglion cells.  II.  An ultraviolet absorption study. Living chick spinal ganglion neurons grown for 19 to 25 days in vitro were photographed with a color-translating ultraviolet microscope (UV-91) at 265, 287, and 310 mmicro. This instrument was unique in permitting rapid accumulation of ultraviolet information with minimal damage to the cell. In the photographs taken at 265 mmicro of the living neurons, discrete ultraviolet-absorbing cytoplasmic masses were observed which were found to be virtually unchanged in appearance after formalin fixation. These were identical with the Nissl bodies of the same cells seen after staining with basic dyes. The correlation of ultraviolet absorption, ribonuclease extraction, and staining experiments with acid and basic dyes confirmed the ribonucleoprotein nature of these Nissl bodies in the living and fixed cells. No change in distribution or concentration of ultraviolet-absorbing substance was observed in the first 12 ultraviolet photographs of a neuron, and it is concluded that the cells had not been subjected to significant ultraviolet damage during the period of photography. On the basis of these observations, as well as previous findings with phase contrast microscopy, it is concluded that Nissl bodies preexist in the living neuron as discrete aggregates containing high concentrations of nucleoprotein.


The fine structure of capillaries and small arteries. Details of capillary endothelia of the mammalian heart are described and compared with capillaries of other organs and tissues. Continuous invagination and pinching off of the plasma membrane to form small vesicles which move across the cytoplasm are suggested as constituting a means of active and selective transmission through capillary walls (12). This might be designated as cytopempsis (transmission by cell). The fine structure of the different layers in the walls of small heart arteries is demonstrated. Endothelial protrusions extend through windows of the elestica interna to make direct contact with smooth muscle plasma membranes. The elastica interna appears to vary greatly in both thickness and density, and probably restricts filtration, diffusion, and osmosis to such an extent that windows and the transport mechanisms described (cytopempsis) are necessary for the functional integrity of the smooth muscle layer. The contractile material consists of very fine, poorly oriented filaments.


Electron microscope studies of early stages of sperm penetration in Hydroides hexagonus (annelida) and Saccoglossus kowalevskii (enteropneusta). 1. The early events of sperm entry in Saccoglossus and Hydroides are described and examined in relation to present knowledge of the acrosome reaction and of egg membrane lysins. In Saccoglossus and several other species these events occur in two phases. First. The acrosome filament of the spermatozoön spans the egg membrane barriers, reaches the reactive egg protoplasm, and causes the egg to begin its fertilization reaction. Second. The filament and its connected sperm head move through the egg membrane barriers and enter the egg proper. The first phase is completed in a matter of seconds but the second phase usually requires several minutes. 2. The peripheral areas of the eggs of the two species differ as seen in sections. In Hydroides, but not in Saccoglossus, the vitelline membrane is bounded by a distinct outer border layer of small concentrically differentiated bodies and penetrated by microvilli from the egg. 3. The acrosome filament, seen in the living condition as a delicate thread in Hydroides and as an exceedingly tenuous thread in Saccoglossus, appears to be tubular in both species when seen in electron micrographs of thin sections. 4. The acrosomal region of Hydroides appears to consist of two components-a peripheral one, which may collapse during the acrosome reaction, and a central one related to the acrosome filament. 5. Deliberately induced polyspermic material was used to increase the probability of finding examples of sperm penetration in thin sections. 6. As seen in sections, areas of low electron density, interpreted as spaces or pits from which the material of the membrane is absent, surround the attached or penetrating spermatozoa. (a) In Hydroides the spaces vary greatly in many characteristics including shape, position in the membrane, and size with relation to the enclosed sperm head. In one specimen a portion of the membrane is missing from border to border; no spermatozoön is seen but immediately beneath the space is the apex of a fertilization cone. (b) In every case in which a determination could be made, the spermatozoön in the membrane has undergone its acrosome reaction. (c) In Saccoglossus some pits are found with which several spermatozoa are associated. Generally, where the spermatozoa are more numerous the pit is larger. (d) Pits similar to those seen in Saccoglossus sections are observed in living eggs. They remain in Membrane I after sperm entry. (e) From the above and other considerations it is suggested that the pits and spaces are formed by local action of a lysin or lysins emanating from the individual spermatozoön at the site of sperm entry. 7. It is considered that the suggested lysin would participate in sperm entry by eroding the membrane barrier in the vicinity of the sperm head, thus permitting the sperm head to pass through the membrane. Since the acrosome filament much earlier stimulates the egg's initial fertilization response, this lysin would facilitate the second phase of the early events of sperm entry.


Structure and development of the chloroplast in Chlamydomonas.  I.  The normal green cell. The cytoplasmic organization of a normal green strain of the alga Chlamydomonas reinhardi has been investigated with the electron microscope using thin sections of OsO(4) fixed material. The detailed organization of the chloroplast has been of special interest. The chloroplast, a cup-shaped organelle, surrounded by a double membrane, consists of: (1) discs about 1 micron in diameter, considered to represent the basic structural unit of the chloroplast, and each composed of a pair of membranes joined at their ends to form a flat closed vesicle; the discs are grouped into stacks resembling the grana of higher plants; (2) matrix material of low density in which the discs are embedded; (3) starch grains; (4) the pyrenoid, a non-lamellar region associated with starch synthesis, and containing tubules which connect with the lamellae; (5) the eyespot, a differentiated region containing two or three plates of hexagonally packed, carotenoid-containing granules, located between discs, and associated with phototaxis. In addition to the chloroplast, the cytoplasm contains various membranous and granular components, including mitochondria, endoplasmic reticulum, and dictyosomes, identified on the basis of morphological comparability with structures seen in animal cells. The nucleus, not investigated in detail in this study, contains a large, granular nucleolus and is surrounded by a nuclear envelope which is provided with pores and exhibits instances of continuity with the endoplasmic reticulum of the cytoplasm.


Experience in reconstructive surgery with patients having respiratory paralysis.


Iron particles in normal erythroblasts and normal and pathological erythrocytes. Iron-containing granules (40 to 100 A in diameter), in groups or isolated, are present in normal erythroblasts, normoblasts, reticulocytes, and certain pathological erythrocytes. Similar granules are present in macrophages and have been noted in the stroma of erythrocytes following phagocytosis and hemolysis by macrophages. Incorporation of the granules from the macrophage into erythroblasts is presented as a process similar to pinocytosis. The presence of the iron-containing granules within the erythroid cells parallels hemoglobin synthesis.


Electron microscopic and histochemical studies of an unusual crystalline protein occurring in cells infected by type 5 adenovirus.


Osteogenic sarcoma; a critical analysis of 430 cases.


The transfixion hip prosthesis; observations based upon five years of use.


The self-locking metal hip prosthesis.

The self-locking metal hip prosthesis.


The principles of hip-socket arthroplasty.


Surgical repair in recurrent dislocation of the ankle joint.


Impingement exostoses of the talus and tibia.


Epiphyseal arrest for the correction of discrepancies in length of the lower extremities.


Aneurysmal bone cyst; observations on fifty cases.


Criteria for determining the proper level of amputation in occlusive vascular disease; a review of 323 amputations.


Bone changes in chronic circulatory insufficiency; a histopathological study.


Retrosternal dislocation of the clavicle.


The covertebral articulations and cervical foramen encroachment.


Hematogenous infection of closed fractures with Mycobacterium tuberculosis.


Paralytic valgus deformity of the ankle; replacement of the paralyzed tibialis posterior by the peronaeus longus.


Intervertebral-disc degeneration considered as a pressure atrophy.


Swivel for proximal radio-ulnar synostosis.


The arteriographic picture of benign bone lesions containing giant cells.


Experimental studies regarding the possible use of self-curing acrylic in orthopaedic surgery.


Metastasis of pulmonary carcinoma to the phalanges of the hand.


Bilateral arborescent lipoma of the knee.


A torso suspension walker for children.

A torso suspension walker for children.


ROBERT JONES; 1857-1933.

ROBERT JONES; 1857-1933.


Amputations.

Amputations.


Osteochondritis dissecans.

Osteochondritis dissecans.


Amputation stumps.

Amputation stumps.


Preparation of the amputee and stump for limb fitting.


Krukenberg-Putti amputationplasty.

Krukenberg-Putti amputationplasty.


The prosthetic management of congenital deformities of the extremities.


Treatment of osteochondritis dissecans.

Treatment of osteochondritis dissecans.


Osteochondritis dissecans in association with dwarfism.


Osteochondritis dissecans of the hip.

Osteochondritis dissecans of the hip.


Rheumatoid arthritis presenting as tenosynovitis.


Subluxation of the inferior radio-ulnar joint complicating fracture of the radial head.


Dysplasia epiphysialis punctata; report of a case with discussion.


Fatigue fractures of the lower tibia and fibula in the same leg; report of a case.


The torn acetabular labrum; a block to reduction of a dislocated hip.


Fracture-dislocation of hip with displacement of bone fragment into acetabulum during closed reduction.


Dystrophia myotonica associated with familial Paget's disease (osteitis deformans) with sarcomata.


Familial osteodystrophy of the skull and face.


Treatment of tuberculous sinuses and abscesses of osteoarticular origin.


Forward dislocation of the elbow without fracture of the olecranon.


Drop-foot appliance with concealed spring.


Movements of the lumbar spinal column.

Movements of the lumbar spinal column.


Intravascular osteoclasts.

Intravascular osteoclasts.


The normal vascular anatomy of the human femoral head during growth.


Studies of the vascularisation of bone grafts.


Observations on the variability of total serum cholesterol in Johns Hopkins medical students.


Drug therapy for childhood epilepsy.

Drug therapy for childhood epilepsy.


Serum lipoproteins in preclinical and in manifest ischemic heart disease.


THE RESPONSIBILITIES of the medical profession in the use of x-rays and other ionizing radiation; statement by the United Nations Scientific Committee on the Effects of Atomic Radiation.


Ecology and coronary heart disease.

Ecology and coronary heart disease.


Pathogenesis of a case of congenital goiter with abnormally high levels of SPI and with mono- and diiodotyrosine in the serum.


Measurement of the active iodine stores and daily hormonal output of the intact human thyroid.


Daily fluctuation of the serum protein-bound iodine level.


Thyro-pituitary relationships in children with cretinism and hypothyroidism.


Marked depression of the plasma protein-bound iodine concentration in the absence of clinical hypothyroidism during testosterone medication.


Pregnanediol excretion in normal children and in children with various endocrine disorders, including congenital adrenal hyperplasia.


Response of the plasma 17-hydroxycorticosteroid level to gel-ACTH in tumorous and non-tumorous Cushing's syndrome.


Cyclic variations in the eosinophil count during the phases of the menstrual cycle.


Effect of thyroid therapy on the tone and contractility of the urinary bladder in hypothyroidism.


Special considerations in the use of blue tetrazolium for the measurement of alpha-ketols in mixtures with other steroids.


Gonadal dysgenesis with menstruation:  a report of 2 cases.


Effect of estrogen therapy on ceruloplasmin concentration in a man with Wilson's disease.


Effect of androgens on alpha2-globulins in women.


Cyclic changes in female saliva.

Cyclic changes in female saliva.


Influence of meprobamate therapy on the estimation of 17-ketosteroids and 17-ketogenic steroids.


The hereditary transmission of hemoglobin differences in mice.


Treatment of schizophrenia with nicotinic acid and nicotinamide.


Aldosterone excretion in normal subjects depleted of sodium and potassium.


The use of d-amphetamine sulfate as an adjunct to psychotherapy.


The selection of candidates for psychoanalytic training; implications from research on the selection of psychiatric residents.


The effects of cortisone and hydrocortisone on water diuresis and renal function in man.


An electrophoretic study of serum proteins in thyroiditis.


The equilibration of radiosodium (Na24), radiopotassium (K42), and deuterium oxide (D2O) in hydropic human subjects.


The response of rheumatic and non-rheumatic children to streptolysin O concentrate.


The concentration and binding of thyroxine and triiodothyronine by rat diaphragm.


Unesterified fatty acid in human blood plasma.  II.  The transport function of unesterified fatty acid.


The acute calcification of traumatized muscle, with particular reference to acute post-traumatic renal insufficiency.


Sodium transport across the surface membrane of red blood cells in hereditary spherocytosis.


Hemodynamic effects of quinidine: including studies of cardiac work and coronary blood flow.


Studies on the destruction of red blood cells.  XII.  Factors influencing the role of S hemoglobin in the pathologic physiology of sickle cell anemia and related disorders.


Early effects of fat ingestion on lipids and lipoproteins of serum in man.


The tradition of scientific critique.

The tradition of scientific critique.


Early effects of fasting and of carbohydrate ingestion on lipids and lipoproteins of serum in man.


The hemodynamic effects of hexamethonium bromide in the dog, with special reference to splanchnic pooling.


Metabolic studies in paralytic acute anterior poliomyelitis.  I.  Alterations in nitrogen and creatine metabolism.


A psychoanalytic hypothesis concerning sex offenders; a study by clinical psychologic techniques.


Metabolic studies in paralytic acute anterior poliomyelitis.  II.  Alterations in calcium and phosphorus metabolism.


Metabolic studies in paralytic acute anterior poliomyelitis.  III.  Metabolic and circulatory effects of the slowly oscillating bed.


Research in clinical psychology: factor analytic contributions.


Metabolic studies in paralytic acute anterior poliomyelitis.  IV.  Effects of testosterone propionate and estradiol benzoate on calcium, phosphorus, nitrogen, creatine and electrolyte metabolism.


The conceptual and test distinction of neuroticism and anxiety.


Critique of recent developments in personality counseling theory.


The construct validity of the sixteen personality factors test.


Confirmation of nine psychotic symptom patterns.


The Loyola Language Study.

The Loyola Language Study.


Measuring the impairment of the abstracting function with the Proverbs Test.


Evaluation of intellectual potential in hemiplegic individuals.


The prediction of adjustment over a four year interval.


Factor analysis of Rorschach scores of schizophrenics.


Effects of different methods of structuring the Rorschach inquiry upon determinant scores.


Psychometric scales for the Rorschach popular response.


Self congruence, by sex and between the sexes, in a normal population.


Similarity of personality in the sociometric preferences of mental patients.


Self and peer personality ratings of psychotherapists.


The scatter pattern of a Southern Negro group on the Wechsler-Bellevue intelligence scale.


The utilization of a psychologist in ward administration.


Evaluation of modified administration of the California Psychological Inventory.


Seasonal changes in admission rates of a state hospital.


Personality changes following transorbital lobotomy.


The results of psychotherapy with children: an evaluation.


Masculinity-femininity development in children.


Some correlates of affective tone of early memories.


Psychological control patterns within families.


A typology of tests, projective and otherwise.


Responses to inkblots as measures of individual differences.


A factorial study of behavioral and psychological measures of anxiety.


Differences in perceptual and cognitive behavior as a function of experience type.


An item analysis of the Coloured Progressive Matrices (1947).


Diagnostic prediction from emphasis on the eye and the ear in human figure drawings.


Reliability and validity of the n-Achievment test.


Level of aspiration in a group of peptic ulcer patients.


Identification with photographs of people.


The Goodenough draw-a-man test as a measure of intelligence in aged adults.


On WAIS difference scores.

On WAIS difference scores.


The effects of scale and practice on WAIS and W-BI test scores.


A comparison of two methods of estimating full scale IQ from an abbreviated WAIS.


The validity of the Barron ego-strength scale and the Welsh anxiety index.


Subtle and obvious test items and response set.


Testing for stimulus equivalence among authority figures by similarity in trait description.


Specific behavior changes following chlorpromazine.


Use of the semantic differential with lobotomized psychotics.


A scale for measuring minimal social behavior.


Observe reliability of interaction patterns during interviews.


Manifest anxiety and test taking distortion of the blind.


Selection of neuropsychiatric patients for group psychotherapy.


Thyroidectomy and its effect upon oxygen consumption of a teleost fish, Pseudoscarus guacamaia.


A method for screening compounds for adrenocortical activity using the resistance of mice to the effect of cold.


The interrelationships of the adrenal glands of mother and foetus in the rat.


Carbonic anhydrase in the female reproductive tract.  II.  Endometrial carbonic anhydrase as indicator of luteoid potency:  correlation with progestational proliferation.


The destructive effect of cadmium ion on testicular tissue and its prevention by zinc.


The adrenal circulation in the rabbit.

The adrenal circulation in the rabbit.


Effect of destruction of thyroid tissue by radioactive iodine on reproduction in mice.


The adrenal gland in lizards and snakes.


The histology of the adrenal gland of the Prototheria.


Studies on experimental obesity.

Studies on experimental obesity.


The effect of relaxin extracts, progesterone and oestradiol on maintenance of pregnancy, parturition and rearing of young after ovariectomy in mice.


Qualitative differences in gonadotrophic extracts from urine of postmenopausal women.


Effects of oestrone and progesterone on mammary development in the guinea-pig.


Thyroid, salivary and harderian glands in mice exposed to heat.


Growth in the cell populations of the thyroid gland of rats treated with thiouracil.


Factors affecting the survival of the adrenal medulla and associated cortical cells in the anterior chamber of the rabbit's eye.


Enhancement by thyroxine of the adrenal-stimulating effect of somatotrophic hormone.


The excretion of pregnanediol and adrenocortical activity.


The relation of endogenous melanophore-expanding hormone to hyperglycaemia in Xenopus laevis.


Urinary excretion of oestrone, oestradiol-17beta and oestriol in patients with chronic liver damage.


Comparison of biological and chemical estimations of urinary oestrogens.  I.  Urine from normal men and women and a eunuch.


The effect of adrenalectomy on the weight gain of pregnancy in the mouse.


The endocrine control of the extra-uterine weight gain of pregnant mice.


The effect of age on the somatic and visceral response to overnutrition in the rat.  Proc. Soc. Endocr. 60th.


Body weight changes in the mouse during the oestrous cycle and pseudopregnancy.


Metabolic changes on reducing diets.  Proc. Soc. Endocr. 60th.


Obesity, parity and diabetes.  Proc. Soc. Endocr. 60th.


The hypothalamus and carbohydrate regulation.  Proc. Soc. Endocr. 60th.


Growth hormone and blood insulin.  Proc. Soc. Endocr. 60th.


Insulin activity and antagonism in the plasma of diabetic patients and animals.  Proc. Soc. Endocr. 60th.


The antidiabetic sulphonamides.  Proc. Soc. Endocr. 60th.


The role of intestinal bacteria in the development of dietary cirrhosis in rats. Diffuse hepatic cirrhosis develops in rats on a choline-deficient diet within 300 days. Absorbable broad spectrum antibiotics added to the daily diet do not prevent the development of fatty infiltration, but they delay the development of cirrhosis for about 100 days more. Non-absorbable antibiotics added to the daily diet prevent the development of cirrhosis in most rats for as long as 750 days. The superiority of non-absorbable antibiotics to absorbable antibiotics excludes a systemic effect of the antibiotics and demonstrates that intestinal bacteria are largely, if not wholly, responsible for the cirrhosis in rats on a choline-deficient diet.


A streptococcal enzyme that acts specifically upon diphosphopyridine nucleotide:  characterization of the enzyme and its separation from streptolysin O. All enzyme that destroys DPN has been found in fractionated and highly concentrated streptococcal preparations that also contain streptolysin O. The enzyme-streptococcal DPNase-was shown by electrophoretic separation and by other means to be distinct from streptolysin O. It is non-dialyzable, heat-labile, and has optimal activity in the pH range 7.2 to 7.8. The enzyme has a high degree of specificity for DPN, which it splits at the nicotinamide-ribose linkage.


Diphosphopyridine nucleotidase as an extracellular product of streptococcal growth and its possible relationship to leukotoxicity. Among 170 streptococcal strains, there were encountered 98 that yielded culture supernates which caused splitting of diphosphopyridine nucleotide (DPN). All of the latter belonged to Group A, C, or G. Release of DPNase accompanied the growth of diverse antigenic types of Group A streptococci, and data on the frequency of DPNase-producing strains for certain types are given. In contrast, cultures representing 3 species of yeasts and 42 species of bacteria other than streptococci of the Lancefield groups were examined for the presence of DPNase as an extracellular product of growth, but in none of these was the enzyme detected. Of the Group A streptococci examined, 41 strains had pedigrees suggesting that they were the etiologic agents of acute glomerulonephritis, and 39 of these were found to produce DPNase. There is an association between capacity of streptococi to form DPNase and capacity to kill leukocytes. A possible mechanism of leukotoxicity is suggested.


Studies of delayed hypersensitivity in vitro.  II.  Delayed hypersensitivity in experimental mumps virus infections. Guinea pigs experimentally infected with mumps virus develop a delayed, hypersensitive skin reaction following the intradermal injection of heat-inactivated mumps virus. This in vivo hypersensitivity is accompanied by a state of cellular hypersensitivity which can be demonstrated in vitro by the addition of mumps viral antigen to cultures of splenic macrophages, following which they become less motile and undergo lysis. These observations support the hypothesis that the state of hypersensitivity which develops early in mumps virus infections may have a role in the pathogenesis of the disease.


Latent viral infection of cells in tissue culture.  IV.  Latent infection of L cells with psittacosis virus. By maintaining L cells in a balanced salt solution of inorganic salts and glucose (BSS) for 2 days or more, they are rendered incapable of supporting the growth of psittacosis virus (6BC), though it infects such cells and is present intracellularly for as long as 3 days in a non-infectious phase. The addition of an enriched medium to such a culture of cells at any time up to 4 days after infection results in the appearance of infectious virus within these cells, which multiplies and is released from the cells, providing the entire period of exposure of such cells to the BSS does not exceed 6 days, following which the cells die. A latent infection with psittacosis virus in a non-infectious phase has been established in a pure line of cells which possess properties of malignancy.


Enzymatic variants of influenza virus.  I.  Isolation and characterization of slowly reacting enzymatic variants of influenza B virus. Slowly reacting enzymatic variants of the Lee strain of influenza B virus were isolated by the serial application of a technique which concentrated the fraction of the virus population obtained by slow elution followed by passage of this fraction at high dilution in chicken embryos. The variants were stable upon serial passage in chicken embryos and did not differ significantly from the parent virus in any of the characteristics tested other than those relating to the virus enzyme. Enzymatically, the variants had a much slower rate of activity on chicken mucoproteins than the parent virus. Their activity was greater at 25 degrees C. than at 37 degrees C. and was much enhanced by calcium ions and depressed by a calcium chelating agent. The enzyme of the variant virus was more labile to heat than that of the parent virus although their hemagglutinins were equally stable. It was estimated that the variants comprised less than 3 per cent of the original population of the Lee strain of influenza B virus particles.


Neuropathogenicity of group A Coxsackie viruses. Coxsackie virus, Group A, Type 14, has been adapted to adult mice and monkeys and induces in them poliomyelitis-like lesions and, in the case of the mice, flaccid paralysis.


Similarity of host responses elicited by polysaccharides of animal and plant origin and by bacterial endotoxins. Ten polysaccharides, isolated from various animal and plant sources, were selected for comparison with 2 bacterial polysaccharides, typical of Gram-negative endotoxins. The tissue sources were: mouse (kidney, liver, lung, stomach, Sarcoma 37, and Carcinoma 241-6); rabbit skin and chick embryo skin; and tangerine and Bryonia root. The bacterial endotoxins were those of S. typhosa and Serr. marcescens. Their relative potency was determined in inducing the following host effects: fever, tolerance to pyrogenic action, leucocytic changes, the Shwartzman reaction, damage to Sarcoma 37, dermal hemorrhagic-necrosis by epinephrine, enhancement of antibody production, and lethality. Some of the polysaccharides were consistently active in all the host reactions studied; except for pyrogenic activity at high dosage, the other polysaccharides were consistently negative throughout. The mouse tissue polysaccharides elicited all the effects studied; in some instances their potency approached those of the bacterial polysaccharides. It is pointed out that elicitation of the above array of biological phenomena, hitherto considered characteristic of bacterial endotoxins, can be obtained with polysaccharides from animal and plant tissues.


The properdin system and immunity.  VII.  Alterations in properdin levels and resistance to infection in mice following the administration of tissue polysaccharides. High molecular weight polysaccharide complexes derived from normal and neoplastic mammalian tissues were found to combine with properdin and to inactivate C'3 in vitro. These polysaccharide preparations were also found to alter properdin levels and non-specific resistance to Gram-negative infection in mice. In these manifestations, the tissue polysaccharides bore a marked resemblance to bacterial lipopolysaccharides. Some implications of the interactions of tissue polysaccharides and properdin in certain disease states are considered.


Clonal growth in vitro of human cells with fibroblastic morphology; comparison of growth and genetic characteristics of single epithelioid and fibroblast-like cells from a variety of human organs. A methodology has been described for reliable cultivation in vitro of dispersed fibroblastic cells obtained from normal human organs. The procedure has permitted establishment of stable cell lines from almost every sample taken, among which the following organs were represented: skin, spleen, amnion, lung, liver, bone marrow, brain, muscle, and heart. Equally good growth has been achieved with cells from embryonic or adult tissues. The methods previously developed whereby single cells plated in Petri dishes grow into isolated macroscopic colonies can successfully be applied to the plating of human fibroblastic stocks. Plating efficiencies in the neighborhood of 50 to 60 per cent are readily achieved with such strains. The resulting colonies can be picked and clonal stocks established. Fibroblastic morphology is maintained in the colonies arising from every single cell of such clonal stocks. All of the single cells from epithelioid clonal strains also maintain their integrity throughout repeated subculture. Since the difference between clonal stocks of these two types is always maintained whenever the respective single cells are plated in the same medium, regardless of the previous history of these stocks, it may be concluded that a true genetic difference exists in these cell lines. In addition to the morphological differences between epithelioid and fibroblastic cell strains, the latter have more demanding nutritional requirements for single cell growth. Thus, single cells of fibroblastic lines almost never produce colonies with high efficiency unless the growth medium which is sufficient for epithelioid cells is supplemented with embryo extract, or a cell feeder layer. Fibroblastic cells are also more resistant to tryptic digestion of the bond uniting the cells to glass surfaces. By use of differential media, growth of both fibroblastic and epithelioid cells, respectively, has been obtained, from dispersed single cells obtained by trypsinization of a specimen of human embryonic lung.


The role of a natural antibody in the rejection of mouse tumor cells by the chick embryo. Cells of the Krebs ascites tumor of mice grow well in the body of the chick embryo until about the 17th day of incubation, when degeneration of the tumor can be seen in tissue sections and viable tumor cells begin to disappear from the internal organs of the embryo. This death of tumor cells follows the appearance in the chick embryo of serum gamma globulins. Among these are antibodies which can agglutinate the tumor cells in vitro, and destroy their viability. These antibodies occur in the blood without the introduction of any foreign antigen. Their possible origin is discussed. Small numbers of mouse tumor cells growing in the chick embryo are completely eliminated shortly after the time when antibodies ordinarily become detectable. When the number of cells present is larger, viable cells persist longer, and at still higher cell numbers, the embryo or chick is unable to eliminate the tumor, and is itself killed by it. Gamma globulins of older birds injected into young chick embryos bearing growing tumor clear the embryonic organs of viable tumor cells.


Effect of pituitary adrenocorticotropic and growth hormones on the resistance of rats infected with Pasteurella pestis. The influence of highly purified pituitary adrenocorticotropic (ACTH) and growth (somatotropic, STH) hormones on resistance of normal, young adult rats infected with Pasteurella pestis organisms (EV 76) has been studied. The daily dosage of ACTH was 0.1 mg. (25 I.U per mg.) and that of STH was 1.0 mg. When these hormones were administered for 3 days prior to infection (1 LD(50)) and for 4 days thereafter, ACTH treatment resulted in a significant depression of resistance (p = < 0.001). The simultaneous administration of STH not only resulted in a definite counteraction of the depression (p = < 0.001), but resistance was increased to a level significantly above that of the non-hormone treated controls (p = < 0.001). Treatment with STH alone also showed a significantly higher protection when compared to the same controls (p = < 0.05). The results of experiments in which the challenge dose was 1 LD(50) suggested that greater alterations in resistance, whether it be a depression or enhancement, could be obtained by continuing hormone treatment after challenge instead of discontinuing on the day prior to challenge. When animals were treated with a relatively high daily dose (1.0 mg.) of ACTH and challenged with only (1/4) of an LD(50) of organisms, the majority of animals died within 4 to 7 days, whereas either the ACTH treatment or the bacterial dose alone resulted in no deaths. If the hormones were administered for 2 weeks prior to challenge with a high, toxic dose of organisms (4 LD(50)), and discontinued thereafter, there were significant differences in mortality in the various groups during the first 24 hours post challenge. The ACTH treated group showed a marked drop in resistance (p = < 0.001). STH, when given alone, exercised a significant protection (p = < 0.02), and in combination with ACTH, effectively counteracted the depression of resistance to acute, toxic deaths induced by the latter hormone (p = < 0.001). In this particular experiment, practically all animals died within 4 to 5 days, owing to the high challenge dose; the few survivors were in the group that had been pretreated with growth hormone. The maximal loss in body weight following an LD(50) challenge dose occurred by the 3rd day post challenge in all groups except in the ACTH-treated animals. At this time the LD(50) control group had lost an average of 14 gm. per rat, the STH group only 3 gm. per rat, whereas the group receiving both hormones lost an average of 7.5 gm. per rat. The ACTH-treated animals showed the greatest weight loss on the 4th day. Thus, under the conditions of the experiment, the beneficial effect of STH on the maintenance of body weight was demonstrated during the period of acute infection. The peak incidence of death in controls or hormone-treated animals following infection with 1 LD(50) of living organisms occurred on the 4th to 5th day post challenge; the earliest deaths occurred on the 3rd day, while the latest occurred on the 7th day. The peak incidence of death after the 4 LD(50) challenge dose occurred earlier, falling on the 2nd to 3rd day. Death was always accompanied by the characteristic gross pathology which results from infection with Pasteurella pestis organisms, particularly in the animals which succumbed after the 3rd day. Bacterial cultures usually revealed the presence of numerous Pasteurella pestis organisms in the spleen and heart blood at the time of death.


Infection induced by oral administration of attenuated poliovirus to persons possessing homotypic antibody. Four of five individuals possessing homotypic antibody in titers of 8 to 64 were infected on being fed Type III (Leon KP-34) poliovirus attenuated by Sabin by passage through tissue culture. None of the infected subjects or controls showed any evidence of illness which could be attributed to virus infection. There was no evidence of spread of infection to any of the control adult wardmates of the experimental subjects, although the two groups were in close contact: none of the controls excreted virus, none showed any antibody shift. One control who had no Type III antibodies at the start of the experiment was still antibody-negative on the 63rd day of the experiment. Three of the four individuals who became infected had naturally acquired-Type III antibodies; the other had antibodies induced by formalinized vaccine. Virus excretion in the stool was of short duration (7 to 13 days) in the three with natural antibodies, and lasted at least 6 weeks after feeding in the vaccinated child. Virus in the throat was detected only in the two persons receiving the larger virus dose (10(7.5) TCD(50)). In them it was present in small amounts between the 2nd and 6th day after feeding. No virus was detected in the blood of any of the infected individuals. The antibody responses of the four infected individuals were variable. There was no clear correlation with virus dosage, amount of virus excretion in the stools, or presence of virus in the throat. Only the child whose neutralizing antibodies were "Salk" vaccine induced showed a marked CF response. The virus excreted by two of the individuals who became infected, as tested in the 2nd tissue culture passage by monkey inoculation, was slightly more neurotropic than the virus which was ingested. Virus excreted by one of these individuals behaved as a virulent strain when tested by the in vitro plaque virulence test, while that isolated from the other had the characteristics of an attenuated strain in this test.


An analysis of tracking behavior in terms of leadlag errors.


Goal-box cues and pattern of reinforcement.


Learning and performance in a complex tracking task as a function of visual noise.


Perception of nonsense passages in relation to amount of information and speech-to-noise ratio.


Rest and warm-up in bilateral transfer on a pursuit rotor task.


Conflict and information-theory variables as determinants of human perceptual curiosity.


The vertical-horizontal illusion and the visual field.


Differential eyelid conditioning as a function of stimulus similarity and strength of response to the CS.


Contingent partial reinforcement and the anticipation of correct alternatives.


Presidential address.

Presidential address.


National socioeconomic issues confronting medicine.


Dependents' medical care program.

Dependents' medical care program.


Albert Jan Kluyver; 1888-1956.

Albert Jan Kluyver; 1888-1956.


Bacteriocinogenesis in Bacillus megaterium.


The effect of some amino acids on the growth of two varieties of Ophiobolus graminis.


The metabolic significance of the citric acid cycle in the growth of the fungus Zygorrhynchus moelleri.


The pathway of glucose metabolism in Zygorrhynchus moelleri.


The growth of mixed populations of Chilomonas paramecium and Tetrahymena pyriformis.


The production of gram-positive variants by Azotobacter chroococcum.


Pyocyanine biosynthesis by Pseudomonas aeruginosa.


The active agent in nascent phage lysis of streptococci.


On the osmotic behaviour of Desulphovibrio desulphuricans.


The synergistic action of cephalosporin C and benzylpenicillin against a penicillinase-producing strain of Staphylococcus aureus.


Some properties of gram-negative bacilli obtained from a strain of Staphylococcus aureus in the presence of benzylpenicillin.


Carbohydrate metabolism of Paramecium aurelia, variety 4, stock 47.8 (sensitive).


Growth of Trichophyton mentagrophytes and Trichophyton rubrum in increased carbon dioxide tensions.


Semi-solid agar media for rapid drug sensitivity tests on cultures of Mycobacterium tuberculosis.


Acriflavine-resistant mutants of Aspergillus nidulans.


Lactobacillus helveticus.

Lactobacillus helveticus.


The assay of influenza virus particles by haemagglutination and electron microscopy.


The structure of viruses of the Newcastle disease-mumps-influenza (myxovirus) group.


Metabolism of methoxylated aromatic compounds by soil fungi.


A virus-inactivating system from tobacco leaves.


Pyruvate accumulation and development of thiamine deficiency in cultures of Proteus vulgaris.


A study of antigenic variation in Vibrio cholerae.


Multiplication of the virus of foot-and-mouth disease in culture.


The mutation of Corynebacterium pyogenes to Corynebacterium haemolyticum.


The staining of influenza virus filaments.


Some effects of ultraviolet radiation on the pathogenicity of Botrytis fabae, Uromyces fabae and Erysiphe graminis.


On the measurement of carbon dioxide uptake with a glass electrode. 1. It has been shown that the glass electrode method as previously described by the author for measurements of transient rates in photosynthesis is free of systematic errors. 2. Justification has been given for the use of the steady state-gas flow method for measuring rates of assimilation under conditions in which the solution is known not to be seriously depleted of CO(2). 3. The decline of photosynthetic rates under light saturation at CO(2) pressures less than several tenths per cent of an atmosphere has been shown to be a real phenomenon. It has been suggested that there may be a real discrepancy between this finding and those of some other investigators due to a difference in the previous history of the algal suspensions.


The chemistry of insect hemolymph.  II.  Trehalose and other carbohydrates. alpha,alpha-Trehalose, a sugar previously regarded as a product characteristic of certain lower plants, has been identified as a major blood sugar of insects. Trehalose has been isolated in pure form from the blood of pupae of the silk moth, Telea polyphemus, and has been recognized chromatographically in all the insects examined, which comprise 10 species belonging to 5 different orders. Trehalose has been determined quantitatively with anthrone after either chromatographic separation or chemical degradation of other sugars. In larvae and pupae of 4 species of Lepidoptera it ranges from 0.2 to 1.5 gm. per 100 ml. of blood and makes up over 90 per cent of the blood sugar; in larvae of a sawfly, about 80 per cent of the blood sugar is trehalose. In Bombyx mori and Platysamia cecropia, the pupal blood trehalose level is about half that in the mature larva, suggesting utilization of trehalose for glycogen synthesis during pupation. Small amounts of glucose and apparent glycogen are also present in the plasma of these insects. In Bombyx larval plasma there is also 0.04 to 0.12 gm. per 100 ml. of glucose-6-phosphate and smaller amounts of an apparent ketose phosphate.


The effects of hydrostatic pressure upon the normal and narcotized nerve fiber. The properties of the giant axon of the squid Loligo pealii were studied at different hydrostatic pressures from 14.7 to 16,000 psi. At 4000 psi the resting potential, the membrane resistance, membrane capacity, the conduction velocity, the amplitude of the action potential, and the maximal change in the membrane impedance during activity were only slightly affected. At the same pressure the duration of the falling phase of the action potential was increased by about 40 to 60 per cent and the duration of the rising phase by about 20 to 35 per cent. The duration of the membrane impedance change during activity was increased by 50 to 100 per cent at 4000 psi. At pressures even slightly above atmospheric the threshold membrane current was appreciably reduced. At about 3000 to 7000 psi the fiber fired spontaneously. At pressures considerably above 5000 psi the membrane resistance decreased to about one-half to one-third the original value. The narcotizing effect upon the nerve fiber of 3 to 7 per cent ethanol was partly or almost completely opposed by low temperatures or high pressures.


Demonstration of two stable potential states in the squid giant axon under tetraethylammonium chloride. 1. Intracellular injection of tetraethylammonium chloride (TEA) into a giant axon of the squid prolongs the duration of the action potential without changing the resting potential (Fig. 3). The prolongation is sometimes 100-fold or more. 2. The action potential of a giant axon treated with TEA has an initial peak followed by a plateau (Fig. 3). The membrane resistance during the plateau is practically normal (Fig. 4). Near the end of the action potential, there is an apparent increase in the membrane resistance (Fig. 5D and Fig. 6, right). 3. The phenomenon of abolition of action potentials was demonstrated in the squid giant axon treated with TEA (Fig. 7). Following an action potential abolished in its early phase, there is no refractoriness (Fig. 8). 4. By the method of voltage clamp, the voltage-current relation was investigated on normal squid axons as well as on axons treated with TEA (Figs. 9 and 10). 5. The presence of stable states of the membrane was demonstrated by clamping the membrane potential with two voltage steps (Fig. 11). Experimental evidence was presented showing that, in an "unstable" state, the membrane conductance is not uniquely determined by the membrane potential. 6. The effect of low sodium water was investigated in the axon treated with TEA (Fig. 12). 7. The similarity between the action potential of a squid axon under TEA and that of the vertebrate cardiac muscle was stressed. The experimental results were interpreted as supporting the view that there are two stable states in the membrane. Initiation and abolition of an action potential were explained as transitions between the two states.


The contributions of normal and anomalous osmosis to the osmotic effects arising across charged membranes with solutions of electrolytes. The osmotic effect arising across a porous membrane separating the solution of an electrolyte from water (or a more dilute solution) is ordinarily due to both normal osmosis, as it occurs also with non-electrolytes, and to "anomalous" osmosis. It is shown that the normal osmotic component cannot be measured quantitatively by the conventional comparison with a non-electrolytic reference solute. Anomalous osmosis does not occur with electroneutral membranes. Accordingly, with membranes which can be charged and discharged reversibly (without changes in geometrical structure), such as many proteinized membranes, the osmotic effects caused by an electrolyte can be measured both when only normal osmosis arises (with the membrane in the electroneutral state) and when normal as well as anomalous osmosis occurs (with the membrane in a charged state). The difference between these two effects is the true anomalous osmosis. Data are presented on the osmotic effects across an oxyhemoglobin membrane in the uncharged state at pH 6.75 and in two charged states, positive at pH 4.0 and negative at pH 10.0, with solutions of a variety of electrolytes using a concentration ratio of 2:1 over a wide range of concentrations. The rates of the movement of liquid across the membrane against an inconsequentially small hydrostatic head are recorded instead of, as conventional, the physiologically less significant pressure rises after a standard time.


The metamorphosis of visual systems in the sea lamprey. The life cycle of the sea lamprey, Petromyzon marinus, includes two metamorphoses. At the end of a period spent as a blind larva, buried in the mud of streams, a first metamorphosis prepares it to migrate downstream to the sea or a lake for its growth phase. Then, following a second metamorphosis, it migrates upstream as a sexually mature adult to spawn and die. The downstream migrants have a visual system based upon rhodopsin and vitamin A(1), whereas that of the upstream migrants is based upon porphyropsin and vitamin A(2). The livers contain vitamin A(1) at all stages. The sea lamprey therefore exhibits a metamorphosis of visual systems, like those observed earlier among amphibia. The presence of porphyropsin in this member of the most primitive living group of vertebrates, as in fishes and amphibia, supports the notion that porphyropsin may have been the primitive vertebrate visual pigment. Its association with fresh water existence throughout this range of organisms also is consistent with the view that the vertebrate stock originated in fresh water. The observation that in the life cycle of the lamprey rhodopsin precedes porphyropsin is not at variance with the idea that porphyropsin is the more primitive pigment, since this change is part of the second metamorphosis, marking the return to the original environment. The observation that in lampreys, fishes, and amphibia, porphyropsin maintains the same general association with fresh water, and rhodopsin with marine and terrestrial habit, suggests that a single genetic mechanism may govern this association throughout this wide span of organisms.