Experimental Biology and Medicine

Theophylline stimulates the secretion of acid gastric juice in man on oral or intravenous administration.

Cultures of certain acetic acid bacteria from “ropy” beer, when grown with dextrin but not when grown with other common carbohydrates, produce abundant amounts of polysaccharide material which has serological properties like those of the dextran which is produced from sucrose by Leuconostoc mesenteroides. A cell-free enzyme system, capable of causing the conversion of dextrin to material serologically like dextran, has been obtained from one of the cultures.

1. Acute anoxia, sufficient in degree? produces a marked diversion of the renal cortical blood flow in the innervated, but not in the denervated, kidney.

2. Simultaneous study of the reactions of the innervated and denervated kidneys is a simple way of distinguishing the mechanisms of action of different nephrotoxic substances.

1. Many mice infected with a pathogenic strain of Cryptococcus neojormans and maintained, with elevated body temperatures, at 35 to 36°C, lived longer than all infected mice kept at 24 to 27°C.

2. These and previous in vitro studies suggest that a direct effect of temperature should be considered in explaining the degree of natural resistance of rabbits to cryptococcosis.

3. Elevated body temperatures might be useful in assisting treatment of human cryptococcosis.

This paper reports the isolation of a filtrable virus from the feces of patients diagnosed either as non-paralytic poliomyelitis or aseptic meningitis and from 2 patients with “fever of unknown origin.” The agent is similar to that reported by Dalldorf and Sickles₁ in producing paralysis with moysitis in newborn mice. The recovery of virus was correlated with the appearance of neutralizing antibodies in the patients' sera. At least two immunological types of the virus exist. The virus was widespread in this country during the summer of 1948 having also been isolated from the sewage of a number of cities and from flies collected in widely separated areas. Subclinical infection may be produced in chimpanzees by oral administration of the virus. A laboratory worker has been accidently infected with the virus.

The effect of phenergan on the Arthus reaction was investigated, employing a quantitative method for the induction of the reaction. In large but non-lethal doses, the drug was found to inhibit appreciably the development of the more severe Arthus reactions. It is suggested that the action of the drug on the Arthus reaction is related to its effect on capillary permeability. A limited study of the inhibition by phenergan of the toxic effect of a large quantity of streptococcal erythrogenic toxin appears to support this view.

Eviscerate rats (250 g) were given continuous intravenous infusions of glucose and insulin during a period of 2 hours. The glucose load was 64 mg of glucose per 100 g of rat per hour and insulin was given at the rate of 4 units per rat per 24 hours. The solution of glucose and insulin was infused at the rate of 20 cc per 24 hours. The addition of isuprel in concentrations of 1:10,000 and 1:25,000 caused a marked decrease in the glucose tolerance of the eviscerate rats.

The acid and alkaline phosphatases of seminal vesicles and prostate glands of rats were estimated quantitatively in normal animals, castrates, and castrates receiving testosterone propionate.

In both glands the enzymes decrease in activity after castration, are restored to essentially normal levels by androgen therapy. The seminal vesicle is more sensitive than the prostate gland in this respect.

Androgen therapy caused hypertrophy of the glands beyond normal, size, but under the conditions of these experiments, the acid and alkaline phosphatase active was not increased beyond normal levels.

Recent observations by McNaughton and Zeller on the high ‘eserine-in-sensitive’ activity displayed towards ethyl chloroacetate by various crude preparations of pseudo-ChE have been confirmed but the experimental results reported here fail to substantiate their conclusion that the activity of pseudo-ChE towards EClA is insensitive to eserine. The evidence presented here has, in fact, indicated that the activity of any of the cholinesterases towards ethyl chloroacetate is inhibited by low concentrations of eserine, the remaining eserine-insensitive activity being due to ali-esterases. The value of eserine for distinguishing that portion of the hydrolysis of aliphatic esters which is due to the cholinesterases from that due to ali-esterases in crude tissue preparations has been re-affirmed. It would seem that of the three inhibitors tested (eserine, diisopropyl fluorophosphonate, tri-o-cresyl phosphate), only eserine can be relied upon to give a clear cut distinction between cholinesterase and ali-esterase activities in all cases.

Histamine and certain derivatives of imidazole nucleus have been found in trace amounts to exercise stimulatory effects on the growth of K. pneumoniae.

In vivo and in vitro experiments indicated that the inhibition of pyruvate oxidation occurred in animals injected with bacterial endotoxins. The inhibitory factor was probably identical with the toxic “antigéne complet” of Boivin and Mesrobeanu. It is suggested that the inhibition of pyruvate oxidation plays an important role in the toxic effect of endotoxins. The exact mechanism of the inhibition of pyruvate oxidation and the identification of the inhibitor as well as the biochemical nature of other components of the endotoxins remains to be further investigated.

The azo dyes p-dimethylaminoazobtenzene (DAB), m'-methyl-p-dimethylaminoazobenzene (m'DAB) and aminoazobenzene (AAB) were fed to the roach Blattella germanica (L) at varying levels in both crude and synthetic diets. A dietary level of 0.2% of the dyes had little or no effect upon growth rate, survival or reproduction of the insects. However, characteristic lesions at the proximal ends of the Malpighian tubules occurred in roaches fed the dyes. DAB was the most active, m'DAB was next, and AAB was least active of the compounds fed.

The responses of white blood cells and lymphocytes following swimming and following ACTH were compared in rats on a complete diet, in rats on a pantothenic acid deficient diet, and following swimming only in rats recovering from a period of pantothenic acid deficiency. A typical lymphopenia occurred 2 hours after either swimming or ACTH in rats on the complete diet. This response was partially abolished following either swimming or ACTH in the rats on the pantothenate deficient diet. In rats recovering from pantothenate deficiency, there was an increase in lymphocytes 2 hours after swimming followed by a decrease at 4 hours. These results are interpreted as a reflection of the changes in the adrenal cortex induced by pantothenic acid deficiency.

A simple, quantitative method for the microbiological assay of filter paper chromatograms has been described. Some possible applications have also been pointed out.

It is well known that various nutritional essentials are concerned with the maintenance of normal epithelial tissue. As part of a program concerning nutritional deficiencies and gastrointestinal epithelium, we have reported the finding of marked antral gastritis on calcium deficient diets. 1 Similar, less marked and less constant lesions were also reported on thiamine deficiency. Under various conditions of inanition the fundic mucosa will show rather typical areas of hemorrhage. 2 Previously, many papers have appeared on the involvement of nutritional deficiencies in the production of hyperplasia of the forestomach epithelium of rats. 3 In none of these cases, even when modifications were introduced to accentuate the process, have penetrating lesions been observed which could in the narrower sense of the word be designated as ulcers or which resembled typical ulcers as they occur spontaneously in man.

Further observations have shown that on a diet deficient in pantothenic acid penetrating ulcers are produced in rats. The diet contained all the known nutritional factors necessary for growth except pantothenic acid, and had the following composition per 100 g of diet: vitamin “free” casein (Labeo) 18.0; cerelose 71.9; salt mixture 6.1 (Ca 1.0, P 0.55); cottonseed oil 2.0; celluflour 2.0. Incorporated in the oil were 10 mg alpha tocopherol and 1500 international units of vitamin A as carotene. The celluflour carried: thiamine HO and pyridoxine HO 1 mg each; riboflavin 2 mg; niacin 4 mg and 2-methyl-naphthoquinone 0.5 mg.

Out of a larger group covering various age ranges, 45 animals have been autopsied: 23 older rats with an initial age averaging 394 (271-620) days and 22 younger rats starting at 42 to 105 days. The average experimental time for the older animals was 100 (67-140) days and for the younger one 125 (87-185) days.

Sera from an appreciable number of 442 wild rats trapped in several widely separated areas of the United States contained neutralizing antibodies against the EMC group of viruses. The incidence of positive sera varied considerably in different geographic regions with the highest rate (87%) occurring in rats from the state of Mississippi.

Similar serological studies on other species of small wild animals failed to provide evidence of the occurrence among them of natural infection with the EMC viruses.

Thirty-six patients suffering from pruritus of diverse etiology were treated with adenylic acid. In thirty instances there was a subsidence of the pruritus ranging from complete to mild. So far we have been able to find in the rather extensive literature no reference to the beneficial effect of adenylic acid upon pruritus.

1. Ninety compounds related to pteroylglutamic acid have been tested for chemo therapeutic effect against transmitted leukemia Ak 4 in mice.

2. Eighty-two of these compounds showed no chemo therapeutic effect by this particular technic.

3. Four showed slight to moderate effect.

4. Four compounds, 4-amino-N10-methyl-pteroylglutamic acid, 4-amino-9-methyl-pte-roylglutamic acid, 4-amino-9710-dimethyl-pteroylglutamic acid, and 2,6-diaminopurine have definite chemotherapeutic activity as demonstrated by approximately doubling the average survival time of the mice treated with these compounds.

5. The occurrence of an amino substitution in the second and fourth positions of the pyrimidine ring in all these active compounds has been noted.

A purified brucella protein, subjected to further purification and presented in a soluble lyophilized form, has been described. Weighed amounts are placed in glass vials, which, after the addition of a measured quantity of sterile saline buffered solution, produces a product ready for use. This procedure facilitates the use of the product in epidemiological investigation and as a routine diagnostic test.

An acid alcoholic extract of bone did not cause the development of bone when it was injected into the testes of 33 male mice of the Strong A strain. It caused extreme damage to about 2/3 of the testis, producing a subtotal infarction of the area. Since fragments of bone marrow produce bone when transplanted to the testis, whereas extracts from much larger amounts of marrow and bone do not cause the development of bone, it is concluded that the marrow reticulum cells survive grafting and produce the bone.

The incidence of hypertension following unilateral nephrectomy is recorded in 100 rats. The development of hypertension was shown to be dependent on the status of the kidneys at the time of removal of the first kidney. If lesions are present, hypertension develops; if absent or minimal, the animals remain normotensive. The bearing of these observations on current theories as to the pathogenesis of experimental hypertension are discussed.

The effects of unilateral nephrectomy on the weight of the heart and remaining kidney and the influence of various types of diet on the survival period following removal of the remaining kidney were also determined. Enlargement of the heart as a result of hypertrophy, as well as of the remaining kidney, may be correlated with the degree of hypertension induced by unilateral nephrectomy. Removal of potassium from the diet markedly prolongs the survival period following bilateral nephrectomy.

The essential amino acid of legume seeds limiting growth of young rats was methionine in all cases studied, with the exception of pigeon peas, in which methionine and tryptophan were both limiting under the experimental conditions.

Prolonged electrical stimulation of the nervous system of conscious animals requires shielded electrodes which will not injure the nerves or cause undue local tissue reaction. The leads connecting the electrodes to the external electrical circuit must be capable of withstanding the almost continuous motion of a normal animal for periods of several months. The purpose of this report is to describe in detail the construction of electrodes and leads which have fulfilled the above requirements. The production of arterial hypertension by renal artery-nerve or splanchnic nerve stimulation with similar electrodes has been reported. 1 , 2 , 3 , 4

The electrodes are constructed of No. 18 fine silver wire and are imbedded in a molded lucite block (Fig. 1). The silver electrode wire is exposed on the inner surface of the lucite block to provide direct contact with the nerve. The obturator occludes the slot in the block after the nerve is in place. The hollow stainless steel terminal is filled with mercury and connected to a mercury-filled, double lumen rubber tube which provides electrical contact to the external electrical circuits.

A double lumen latex tube joined in a Y at the stainless steel terminal provides a means of flushing and cleaning the mercury columns whenever necessary. 1N HCl, followed by water, alcohol and air, is injected into one tube, flowing through that tube, through the hole in the stainless steel terminal and out through the second tube. Then this system is refilled with clean mercury.

Construction of electrodes. The electrode blocks are molded from powdered Lucite† at a temperature of 175°C and a pressure of approximately 1000 lbs./in 2 (Fig. 2).

Step 1: (Fig. 2, photo 1). The silver wire (b) is wrapped around the mandrel (c) and soldered to the stainless steel terminal (a). Soldering flux designed for stainless steel facilitates this step.‡

A method for the quantitative determination of minute amounts of digitoxin in urine is described. The renal excretion of digitoxin is negligible in the rat.

Approximately 60% of the succinoxidase activity of rat pituitary glands were found to be associated with the large granule fraction, and more than 50% of the gonadotrophin of these glands was associated with two granule fractions isolated from sucrose homogenates by differential centrifu-gation. The supernatant fraction from which the granules were removed contained the remaining gonadotrophic activity. The gonadotrophin can be extracted from the isolated granules with isotonic sodium chloride solution.

Nitrogen balance studies on 3 male rats during periods of normal control, of alloxan-induced diabetes with insulin therapy, and of fatal acidosis after withholding insulin, are reported.

The pattern of excretion of urinary amino-acids, and the ratio of total amino-acid nitrogen to total urinary nitrogen remained essentially unchanged throughout the 3 periods, including the terminal stage with greatly increased losses of total nitrogen.

1. Electrophoretically and chemically separated fractions of human serum containing high concentrations of mucoproteins showed no increase in non-specific hyaluronidase inhibitor when compared to native serum or other mucoprotein-poor fractions of serum.

2. In children suffering from “lipoid nephrosis” the hyaluronidase inhibitor levels of the serum were higher while the muco-protein levels were significantly lower than normal.

3. In spite of the striking statistical correlation existing between the serum levels of mucoprotein and non-specific hyaluronidase inhibitor in a wide variety of human diseases, marked disparity in the serum levels of these substances occasionally occurs.

4. On the basis of these findings the lack of identity of the non-specific hyaluronidase inhibitor and these serum mucoproteins is pointed out.

With 3 strains of Leuconostoc it was found that biotin was required for growth in media containing invert sugar, glucose, or fructose. In a sucrose medium the organisms were free of a biotin requirement to the degree that the disaccharide was utilized via the mechanism resulting in dextran synthesis.

The intravenous administration of 0.5 mg of dihydroergocornine to 24 patients with left ventricular hypertrophy caused no electrocardiographic changes indicative of coronary vasoconstriction. Although 6 of the 24 patients suffered from anginal pain and many more certainly had coronary disease, no angina pectoris followed the injection.

This particular alkaloid of ergot seems to be a safe drug in patients with coronary artery disease.

Using the yolk sac method, a strain of pseudorabies virus has been cultivated in eggs for 50 serial transfers. That the virus multiplied in the yolk sac was shown in 4 ways: (1) suspensions of yolk sacs from infected eggs that had been transferred either for-5, 12, 26, 40 or 50 passages produced disease in rabbits, guinea pigs and mice; (2) the effects in animals of virus that had been transferred for 50 serial passages was neutralized by antiserum that neutralized virus passed in rabbits; (3) the yolk sac contained as much or more virus than either the chorioallantoic membranes, chorioallantoic fluid or embryos; (4) the virus produced characteristic intranuclear inclusions in the yolk sac cells like those seen in cells from infected animals.

With continued transfer of pseudorabies virus in eggs, embryos died 40 hours after inoculation while in the initial passage only 60% of the embryos died after 3 days. The capacity to invade certain parts of the egg such as the chorioallantoic fluids and embryos increased and more extensive changes were produced in the embryo. Continued passage also altered the effects on rabbits, guinea pigs and mice. The period of time from inoculation until death of animals lengthened, the local pruritus produced by subcutaneous inoculation of virus passed in rabbits no longer occurred and infected animals lived longer after showing signs of illness.

The previously reported antagonism of choline and heparin was studied in vitro and in vivo. When choline and heparin were mixed in whole plasma and the prothrombin time determined, the choline had no effect on the action of heparin. Choline alone slightly prolonged the prothrombin time. Choline and heparin do not combine chemically as shown by spectrophotometric determination. In vivo, choline has no effect on the action of heparin.

1. Five patients moderately to severely ill with myasthenia gravis received 400 mg adrenocorticotrophic hormone given in amounts of 20 mg every 6 hours.

2. Changes that may indicate the beginnings of an incomplete remission occurred after completion of the injections. These changes consisted of decrease of the symptoms and outward manifestations of muscle dysfunction, disappearance of the abnormalities noted in the electromyogram, increased work performance on the ergograph, and increase to normal of the ability of serum to support acetylcholine synthesis. The incomplete remission is long lasting.

1. The alkaline and acid phosphatase activity was determined on whole homogenates of embryonic chick retina from the 12 th day of incubation until 3 days after hatching.

2. The alkaline phosphatase activity increases slowly up to 16 days and then more rapidly to 19 days, when it reaches a maximum. After the 20th day it begins to decrease until 3 days after hatching, at which time it establishes a level of activity which is apparently constant throughout the life of the chicken.

3. The acid phosphatase activity is considerably higher than the alkaline at 12 days, but shows only a slight increase up to 19 days, after which it also falls to a new level.

4. Since the rise in activity of both acid and alkaline phosphatase correspond closely to the period of cellular maturation in the chick retina, this seems to give added support to the concept that these enzymes may be associated with the histochemistry of differentiation.

Eviscerate male rats were given continuous intravenous infusions of solutions containing glucose and insulin. The times of survival were determined by a heart-beat recorder. The substitution of Tyrode's solution and of 5% gelatin for 0.9% sodium chloride in the infusion fluid failed to prolong survivals. The rats which were eviscerated without sterile technic developed septicemia and peritonitis. The attempts to maintain asepsis during the procedure of evisceration were not uniformly successful, but the average survival of 26 rats operated under “aseptic” conditions was 3113 ± 67 minutes as compared to 2743 ± 109 minutes for 26 rats operated without asepsis. The maximum survival time recorded for any animal was 63 hours and 47 minutes.

1. Young white mice of 12 to 15 g body weight fed diets containing 50% Lathyrus odoratus meal grew well and showed no development of experimental lathyrism in 17 weeks, although young white rats which received a similar diet developed experimental lathyrism in from 3 to 6 weeks. 2. Diets containing Lathyrus latifolius meal (50%) were toxic for both rats and mice, death occurring in from 3 to 8 days (rats) and 5 to 12 days (mice). The extraction of seed of Lathyrus latifolius meal with 30% ethanol removed the toxic principle. Mice fed the extracted meal survived and appeared normal over a period of 18 days. 3. Mice fed Lathyrus sylvestris seed died with symptoms of acute toxicity in 4 to 7 days.

Glycogen is present in rachitic cartilage only in the most recently matured hypertrophic cells. The broad zone of hypertrophic cells beneath is devoid of glycogen. This localization coincides with the area where inorganic elements deposit during the initial stages of healing and furnishes further evidence for the relationship of glycogen, and possibly the glycogenolytic cycle, to the calcification mechanism.

In patients with hypertensive vascular disease, the simultaneous administration of an adrenal cortical extract appears to block the pressor effect of deoxycorticosterone acetate when used alone.

Severely diabetic depancreatized male rats reacted as usual to protamine zinc insulin administration by reducing their food intake but gaining weight through a reduction in the glycosuria. Desoxycorticosterone acetate in large doses was without measurable influence on the body weight gain or glycosuria. The glycosuria of the severely diabetic rat without insulin therapy and receiving food ad libitum was unaffected by similar doses of desoxycorticosterone acetate.

The “4-amino” pteroylglutamic acids profoundly inhibit the growth of the chick embryo, with the production of developmental abnormalities. These compounds are active in the range of 0.003 to 0.005 mg/egg, and their actions are not prevented by large doses of folic acid. The “4-amino” folic acids with aspartic acid, threonine and alanine substituted for the glutamic acid are considerably less toxic but produce similar toxicological effects. Other compounds allied to folic acid are relatively non-toxic and do not possess the growth-inhibitory activity of the “4-amino” compounds.

2,6-diaminopurine, at LD30 doses, does not seem to be an active growth inhibitor, but it produces a pale embryo, presumably deficient in hemoglobin.

Experiments are reported in which it was found; that CaC'4O₃ implanted intraperitoneally in rats produced a qualitatively similar isotope distribution pattern in the liver glycogen, and blood glucose and lactate. This result suggests that in isotope feeding experiments, analysis of the blood glucose and lactate may yield information comparable to that obtained by the degradation of liver glycogen. Additional experiments to put this question to a more critical test are in progress.

The antifungal activity of some partially purified extracts of two actinomycetes was sharply increased by filtration through gradocol membranes.

1. A specific strain of salmonella has been invariably obtained on culture from the ulcers of rat cecitis, 2. Salmonella were not obtained from the cecum in the absence of lesions with one exception. 3. Agglutinins for the specific strain of salmonella are found in most of the rats in this colony although the titer is on the average higher in animals with visible cecitis. 4. Feeding the specific salmonella in appropriate doses was followed after a long latent period by development of cecitis in many of the test animals. 5. The association of some other synergistic agent is not fully excluded but seems at present unlikely.

Maeroscopically and microscopically, oviducts of frogs receiving aminopterin (4-amino pteroylglutamic acid) failed to respond to the growth stimulating action of estradiol. However, a significantly greater number of mitotic figures were visible in these oviducts, Evidence is presented to suggest that the folic acid antagonists may exert their growth inhibitory action by interfering with folic acid utilization in the organism, with a consequent reduction in nucleic acid synthesis, and a retardation of the rate of cell division.

1. Rats which died 3 to 5 days after total-body irradiation of 809–972 r showed an elevation of oxygen consumption of about 35% occurring within 24 hours.

2. Rats which died 9 to 10 days after doses of 648 to 972 r showed an increase in metabolism of about 58% and a decline prior to death.

3. Rats which survived doses of 648 r showed an average increase in, oxygen consumption of 32% during the first week, and less pronounced increase extending over a period of at least 16 days after irradiation.

4. At doses from 54 to 432 r there was an increase in metabolism by about 8 1/2%. The maximum oxygen consumption, was reached later at sublethal rather than at lethal doses.

5. Increased metabolism did not coincide with weight loss either in time course or in dose dependence.

1. A lymphocyte decrease occurs within 2 hours following the removal of the tourniquet in fatal shock induced by leg tourniquets in albino rats. 2. There is no decrease in the percent of lymphocytes in blood smears made below the tourniquet at the end of a 5-hour period. 3. Dibenamine hydrochloride increases the onset of death in tourniquet-shock and increases the lymphocyte decline.

The inactivation of thrombin by heat is sharply inhibited, if it is mixed with equal parts of heparin. Heating a mixture of thrombin-heparin (1:1) for 10 minutes to 100°C causes only a slight decrease of activity.

Comparisons were made between the oxygen consumption and increased movements induced by the central nervous excitatory effects of a number of physiologically active organic compounds. After injection of several of these compounds, benzedrine, desoxyephedrine and N-methyl-β-cyclohexylisopropylamine HCl, oxygen consumption and voluntary movements varied in direct relationship to each other. After the injection of another compound (Isuprel), oxygen consumption increased greatly, but there was a decrease in activity. Oxygen consumption can be used as a measure of voluntary muscular activity only under limited conditions.

In a single chicken embryo, we find all that is required for preparing tissue cultures: the ingredients of the culture medium as well as the explant. Salt-glucose mixtures are replaced by amniotic fluid from the same embryo from which the tissues are obtained. An egg shell sector about 1 1/4 inches in diameter is cut out of the large egg pole on the 8-9th day of incubation, and the contents are poured cautiously into a Petri dish so as to avoid bursting the very delicate amniotic membrane. The membrane is then punched with a thin, sharp cannula and 2-3 cc of amniotic fluid are aspirated. The shell sector should not be larger than indicated, otherwise the amniotic membrane may be easily damaged. Only completely transparent fluid should be used; turbid fluids are mixtures of yolk and amniotic fluid and will inhibit growth. Tissue for explants is then cut out and the remaining embryonic tissue provides the embryonic juice. The culture medium consists of embryonic juice and amniotic fluid 1:1. The excess of the amniotic fluid may be used for all purposes where saline or other salt mixtures are usually used, e.g., washing of tissue, etc. The growth of cultures in this medium is not inferior to the growth of cultures in other fluid media. The cells are as normal in appearance as cells from a plasma culture (Fig. 1). Amniotic fluid not only replaces but also, in many regards, surpasses Tyrode's and other salt-glucose solutions in that it does not require sterilizing, filtering, or pH-adjusting. This liquid medium method may be recommended for cultures where the primary medium is to be removed for experimental purposes and replaced by other media.

With the aid of an easily constructed needle a method has been devised for obtaining growth curves of influenza virus in individual embryonated eggs.

The classic substratum for tissue cultures, developed by Harrison 1 Burrows, 2 and Carrel, 3 consists of chick plasma clotted with chick embryo juice and with an overlay of embryo juice variously diluted. Such a plasma clot without embryo juice overlay is insufficient to support prolonged tissue growth except when frequently renewed by transplanting the cultures to fresh substratum. It supplies an ill-defined but far from negligible level of nutritional factors. In any precise study of cell nutrition, these factors must either be clearly defined or, if possible, eliminated before the substratum can be satisfactorily evaluated as a base line. Various attempts have been made to arrive at such an evaluable base line. Porter and Hawn 4 have used clots prepared from purified fibrinogen coagulated with thrombin. Both these substances are more clearly defined and more nearly inert than are plasma and embryo juice, but they are still not completely defined. Evans and Earle 5 have been successful in developing a procedure for cultivation of tissue cultures on sheets of perforated cellophane, which is nutritionally fully inert. This is a very satisfactory solution of the nutritional problem, but such cellophane is not easily available to all workers throughout the world. Lewis, 6 White, 7 and others have grown cultures directly on glass. This is likewise a fully satisfactory solution of the nutritional problem but the results obtained are somewhat unreliable.

Fischer 8 has approached the problem from quite a different angle by seeking to eliminate the nutritional factors from the classic plasma clot. He showed that when chick plasma and embryo juice, after thorough dialysis against a dextrose-Ringer's solution, were used in the preparation of clots on which to cultivate chick fibroblasts, no growth whatever would occur thereon.

The administration of 4-amino-PGA to dogs produced a sprue-like syndrome with diarrhea, peripheral leucopenia, depletion of bone marrow with increased numbers of hyper segmented polymorphonuclears and giant metamyelocytes, abnormal nuclear disintegration of normoblasts, change of nuclear pattern in erythroid elements and megalo-blasts. Doses given were lethal and animals succumbed with anorexia, weight loss, dehydration, and hemorrhagic diarrhea following severe ileitis and ulcerative colitis. It is suggested that the syndrome results from antagonism of folic acid.

Gamma benzene hexachloride, mixed with highly purified rations, is toxic to the weanling and adult albino rat. The addition of inositol does not alleviate the toxic symptomatology of γ-BHC.

If used in thin sheets with a minimum of tissue injury isolated skeletal muscle in the form of the internal oblique muscle of the rat forms more glycogen under the influence of insulin just as does the specialized muscle comprising the diaphragm. Desoxycorticosterone reduces the amount of glycogen formed by incubation with glucose alone as in the case of diaphragm muscle. Skeletal muscle offers new material for further investigation of the action of insulin.

Lactic acid, pyruvic acid, inorganic phosphorus, phosphocreatine, and ATP-ADP were determined in liquid air fixed brains of normal and convulsed cats. In normal brains the levels in cerebellum and cerebrum were approximately the same. In convulsed brains, however, the lactic acid increases were much smaller and phosphocreatine levels were higher in cerebellum than in cerebrum despite the fact that seizure activity was approximately of equal intensity in both parts.

The brains of normal monkeys and those treated with carbon dioxide and electric shock were fixed with liquid air and analysed for lactate, pyruvate, and acid-soluble phosphates. The levels of these constituents and their change under the above conditions were shown to be of the same magnitude and in the same direction as those found in similarly treated dogs, cats, and rats.

The net effect of a sufficiently cold environment is to lower the resistance of mice to the lethal action of X-rays.

Subjection to a 10° or 30°C environment for 2 weeks prior to irradiation favors survival of irradiated mice maintained in those environments.

Mice kept in a 30° environment that die following irradiation frequently show fatty changes in the liver.

Several substituted nitrobenzenes including chloramphenicol (Chloromycetin) show inhibitory activity against the viruses of meningopneumonitis, lymphogranuloma venereum, cat pneumonitis, and mouse pneumonitis. Several nitrofurans were also shown to inhibit the growth of these viruses. The chemotherapeutic activity of these various substances is compared and the relation of chemical constitution to activity discussed. Although chloramphenicol is probably the least toxic of the substances tested, it did not show striking superiority to other nitro-com-pounds in activity against viruses of the psittacosis-lymphogranuloma group under the conditions of these experiments.

p-Arsenobenzamide and its dithioglycollate have a definite inhibitory activity against the viruses of mouse pneumonitis and cat pneumonitis in the lungs of mice. The dithiogly collate also inhibits growth of the agents of meningopneumonitis and cat pneumonitis in the allantoic sac of chick embryos.

The kidney, liver, heart, small intestine and femoral muscles of rats raised on a corn-soybean diet were assayed for vitamin B₁₂ content.

The kidney was found to be the site of greatest B₁₂ concentration. The liver, heart, small intestine, and muscle contained no appreciable amount of the vitamin after the animals had been kept on the basal ration for 6 weeks. The amount of B₁₂ increased in the organs and tissues when vitamin B₁₂ was added to the diet.