Experimental Biology and Medicine

Adult rats maintained on a purified diet containing succinylsulfathiazole and supplemented with all the known vitamins except pteroylglutamic acid from one to 3 months before breeding showed impaired reproduction.

The natural and synthetic estrogens are important in controlling the function of reproductive tissues, and they are also known to affect the metabolism and function of other tissues not directly concerned with reproduction. It is probable that these changes depend basically on the part played by the estrogens in certain of the enzymatic processes concerned with cellular function. As a means of obtaining information on these basic cellular processes McShan and Meyer 1 studied the effect of the estrogens on the succinoxidase system of liver and pituitary tissues. It was found that both natural and synthetic estrogens were effective inhibitors of this system, and that the inhibition was mediated through the action of the estrogens with the cytochrome oxidase of the system. This work has been extended to the study of the effect of the estrogens on the malic dehydrogenase system using the method reported by Potter 2 for the determination of this dehydrogenase. In addition results are given on the activity of malic dehydrogenase when the cytochrome c of the system is replaced by brilliant cresyl blue.

Experimental. Male and female rats of the Sprague-Dawley strain which were three to four months old were used in these experiments.

The rats were killed by decapitation and the tissues were removed immediately, weighed and placed in sharp-pointed homogenizing tubes containing 0.1 ml of glass-distilled water. These homogenizing tubes containing the tissues were kept in an ice bath during homogenization and until the tissues were placed in the Warburg flasks.

The method of Potter 2 for the determination of malic dehydrogenase was followed in these experiments. Two and one-half per cent water homogenates of the liver tissue were used throughout. Conventional Warburg flasks without side arms were employed.

The cause of hemochromatosis does not appear to be a defect in the formation of ferritin in the duodenal mucosa or the liver.

The sparing action of protein on the pantothenic acid requirement of the rat has been confirmed by using a protein considerably lower in pantothenic acid, washed beef blood fibrin, instead of casein as the protein component of the diet. Despite the accentuation of the pantothenic acid deficiency produced by substituting purified fibrin for casein at the 24% level, doubling the fibrin level resulted in significantly better growth and survival. The differences in growth and survival between the two protein levels in the fibrin-containing diets were more pronounced than those observed for the casein-containing diets. The protective effects of the high fibrin diet indicated also that phosphorus can be eliminated as a possible factor concerned in the sparing action.

In the male rabbit, early fetal castration (before the 21st day) prevents the formation of male secondary sex characters such as the prostate. At a later stage (24 days) established primordia continue their development even after ablation of the testes; the resulting structures are usually subnormal. The effects induced by testicular secretions are sometimes regionally restricted. Earlier observations on the differentiation and persistence of female genital ducts after early orchidectomy are confirmed and extended.

Adrenalectomized rabbits with hypertrophy of the lymphoid tissues produce antibodies in amounts far in excess of that produced by intact animals. this is evident not only by definite reactions in higher dilution but by the more masive precipitate in low dilutions. The prevention of the lymphoid hypertrophy by administration of adrenal cortical hormones does not reduce the amount of antibodies in the sera. This is probably due to the disruptive action of the hormone on the lymphocyte with a more rapid release of the immune globulin than would normally take place.

1. Twenty-two of 25 dogs fed a kennel diet of selected table scraps to which was added each day for 8 weeks or longer 3.0 cc/kg of cod liver oil developed typical arterial lesions when they died in uremia 7 to 35 days after the experimental production of renal insufficiency.

2. When vitamin E (mixed natural tocopherols, 2.5 to 4.0 mg/kg/day by mouth) was administered along with the diet, none of 4 dogs subjected to the same experimental procedures developed any arterial lesions.

3. Vitamin E was equally effective in preventing or retarding the arterial lesions when its administration by mouth was started 0, 1, and 2 days after renal insufficiency was induced.

Experiments with delayed supplementation of tryptophane show that cataract formation in rats occurs even after consumption of relatively large quantities of tryptophane. It seems that like growth promotion, cataract prevention by this amino acid can be accomplished only when it is supplied simultaneous with the other essential amino acids.

Baseline movements which simulated impure auricular flutter developed following intravenous epinephrine injections. These are shown to be extracardiac in nature. They are induced by extreme tachypnea and the diaphragmatic movements associated with retching and vomiting.

A procedure has been devised for the quantitative evaluation of the activity of the enzyme which degradates quinine. Pamaquine and atabrine were found to suppress the enzymatic degradation of quinine by a liver homogenate.

Rats have been fed diets deficient in tryptophane, riboflavin or nicotinic acid and the amounts of microbiologically available histidine, arginine, threonine, phenylalanine and tryptophane excreted in the urine were determined. No large changes were noted in the amounts of these amino acids excreted in the urine when rations deficient in nicotinic acid were fed. Rats fed a riboflavin or a tryptophane deficient diet excreted approximately twice as much of the ingested amino acids as animals fed adequately supplemented diets. In all cases, however, the amounts excreted were small, less than 2.5 per cent of those ingested. After acid hydrolysis of the urine samples, a 2-4 fold increase was observed in the values for histidine, arginine, threonine and phenylalanine.

Vasoconstriction of the isolated vessels of the rabbit's ear follows the addition of fresh plasma to perfusates containing liver preparations that are in themselves inactive. The activation caused by plasma is indistinguishable from the effect of subthreshold amounts of epinephrine added to these tissue fractions. Incubation of plasma, known to result in loss of its epinephrine content, also causes loss of its vasoconstrictive influence on perfusate containing liver fractions.

Male mice bearing sarcoma 180 implants exhibit an impairment in their ability to store liver glycogen after glucose administration. This is similar to the defect in patient with gastric cancer.

The catalase and arginase activities of liver biopsies from 16 patients bearing gastric cancer did not differ significantly from those of 11 patients having benign gastric lesions. These results are in contrast to those found in animal experiments, and are in contrast to those obtained with certain other liver function tests which appear to be impaired in patients with gastric cancer.

The relationship of the serum protease to the action of peptone was investigated using soybean trypsin inhibitor and protamine. Soybean trypsin inhibitor inhibited fibrinolysis by chloroform serum (activated serum protease). It inhibited the fibrinolysis occurring in peptone shock in the anterior dog and also the release of histamine from rabbit blood cells in vitro on the addition of peptone. Protamine accelerated fibrinolysis in the anterior animal and also lysis by the serum protease in the presence of the natural serum protease inhibitor.

We wish to acknowledge the hospitality of Dr. C. H. Best in the Department of Physiology, University of Toronto. We are indebted to Dr. E. Fidlar for the platelet counts.

It was reported previously 1 that hamsters, when allowed to feed upon St. Louis encephalitis virus, either die with encephalitis, or develop an immunity as evidenced by appearance of serum antibody and resistance to intracerebral inoculation. Subsequent tests have indicated that hamsters, fed Japanese encephalitis virus react in. much the same way. The present report describes the extent of the infection in hamsters following feeding with St. Louis (Hubbard strain) and with Japanese (Nakayama strain) encephalitis viruses, as determined by subinoculation of mice with various tissues.

The possibility of infection by way of the alimentary tract with neurotropic viruses, other than those of poliomyelitis and encephalomyelitis of mice, has received some attention. Infection of mice by introduction of St. Louis virus into the alimentary tract has been described by 2 groups of investigators, 2 , 3 and both report development of immunity in survivors. The latter group also fed 2 hamsters with St. Louis virus and found neutralizing antibody some days later. 4

In our experiments hamsters were induced to eat virus by starving them overnight, and offering them the heads of infected mice. Tissues to be tested for virus were carefully removed from exsanguinated animals with separate sets of instruments, emulsified in a minimum quantity of broth to which 10% normal sheep serum had been added, centrifuged, and the supernatant inoculated into 3 or 4 mice each. In the case of bacterially contaminated tissues such as the intestine, the specimens were washed repeatedly in sterile physiological saline and were thereby rendered sufficiently free of bacteria to allow intracerebral inoculation.

In most of the experiments a second intracerebral passage to mice was made with the brain tissue of any mouse found ill or dead, in which there was doubt concerning the cause.

1. The implantation rate in female rats on a purified diet containing about .1-.4 mg of tocopherols per 100 g diet was compared with the implantation rates in animals on the same diet receiving single and continuous supplements of synthetic dl alpha tocopherol acetate.

2. Failure of implantation was observed after the eighth month in females without tocopherol supplements. With continuous tocopherol administration, the implantation rate was normal after one year. Single post-mating tocopherol supplements increased the implantation rate in older rats significantly. The requirements necessary for successful implantation in older rats vary widely and increase steeply with age.

3. Infections of the uterus and the tubes were frequently observed in the deficient rats, but not in those on the complete diet. Presence of infection does not explain the higher implantation rate after single post-mating tocopherol doses.

4. The changes leading to the failure of implantation are prevented, but once present, only partly counteracted by alpha tocopherol acetate.

Excision of one or both atrial appendages is feasible in dogs.

The ureters were ligated in 6 dogs, and phthalylsulfathiazole was administered orally in doses of 0.5 to 0.75 g/kg/day for 3-6 days pre-operatively and postoperatively until death. Two of these animals showed at autopsy an increased vascularity of the fascial sheath covering the perirenal fat, 5 animals showed perirenal sheath hemorrhage, and 3 animals had fresh free blood in the abdominal cavity.

The ureters were ligated in 6 control dogs, and they received no phthalylsulfathiazole. Four of these animals showed at autopsy an increased vascularity of the perirenal sheath. None of the animals showed perirenal hemorrhage.

It was found that both ureter ligation and phthalylsulfathiazole administration are necessary for production of the perirenal lesions. It appears that the perirenal hemorrhage is due to vascular changes since no abnormalities in prothrombin time, bleeding, clotting, and clot retraction time, red blood cell counts or platelet counts were demonstrated. The average total blood sulfathiazole concentration at the time of death in the test animals was 2.9 mg %.

An antigen from the yeastlike phase of Histoplasma capsulatum fixed complement in the presence of antisera from experimentally infected rabbits from the 2nd to the 23rd weeks following infection. In contrast to histoplasmin, this antigen did not react with several other fungal antisera.

Sulfactin is active primarily against gram-positive microorganisms. The LD50 for mice of 17-20 g by intraperitoneal injection is about 2,750 μ. The amount of sulfactin required to protect mice against the intraperitoneal injection of approximately 1000 minimum lethal doses of Diplococcus pneumoniae, type 1, is of the order of 1 to 7.5 μg.

Induced type transformation of Sh. paradysenteriae (Flexner) has been obtained in 3 out of 225 experiments. The inducing principle is contained in filtrates of broth cultures.

The ovarian hyperemia reaction in immature rats was studied following the subcutaneous injection of equine serum from 38 mares and 4 female donkeys, 42-138 days after natural insemination. The accuracy of this 24-hour pregnancy test was 83%, failures being observed both by negative reaction in 4 pregnant cases and positive reaction in 3 non-pregnant ones.

Acknowledgment is due to M. X. Camargo, J. Vieira and S. Fontes for kindly supplying the blood samples tested.

: It has been demonstrated that the blood group isoagglutinins, immune anti-A agglutinin, and Rh agglutinating and blocking antibodies are inactivated or destroyed relatively rapidly with 1:1000 dilution of ozone in oxygen.

So far as Rh agglutinating and blocking antibodies are concerned, our results are in essential agreement with the observations of others with respect to the action of physical factors such as temperature and pressure.

There appears to be no conversion of Rh0 agglutinating antibody to Rh0 blocking antibody by treatment with ozone.

This report presents data concerning the ability of rats treated with cytochrome C to withstand the anoxia of high altitude exposure. The survival rates of experimental animals given an intraperitoneal injection of 5 mg of cytochrome C in isotonic saline were compared with those of control animals treated with a similar amount of saline. Groups of control and experimental animals were exposed simultaneously for periods of one hour. Altitudes of 33,000 and 35,000 feet were employed. In both instances, the survival rate was higher in the control group. In is concluded, therefore, that the intraperitoneal injection of cytochrome C is not effective in protecting rats against the anoxia of high altitude exposure.

1. A new class of highly tuberculostatic agents of low toxicity is described. This group comprises many 2,6- substituted derivatives of benzothiazole. 2. Several of these derivatives are active therapeutic agents in guinea pig tuberculosis. 3. Structure activity relations and possible modes of action are discussed.

1. The effect of X-ray irradiation on the respiration of the nuclei of fowl erythrocytes has been investigated. 2. The respiration of these nuclei was temporarily stimulated by treatment with doses of 500,000 to 1,500,000 r. This stimulation of nuclear respiration was more pronounced than that obtained with whole erythrocytes. 3. The addition of hemolyzed blood or albumin to the suspension of nuclei before irradiation has a protective effect against the activating influence of X-rays.

During the course of tracer studies with Na²² † in 2 patients with chronic congestive heart failure and one normal subject, the relationship of weight, venous pressure and sodium excretion was observed.

Each subject received an intravenous injection of a tracer dose of Na²² (activity of 12,500,000 counts per minute 1 ). Over a 2-month period, all urine samples were collected separately and the concentration of radio-sodium determined for each, as well as for daily samples of blood serum. All counts were corrected so as to correspond to an initial injection of Na²² with an activity of 20,000,000 counts per minute per 100 lb body weight. Weights and venous pressures 2 were recorded daily.

Results. (1) Behavior of weight, venous pressure and sodium excretion with the subjects on a low sodium diet. In all 3 subjects during a 22-day period of low sodium intake (<1.7 g NaCl/day), the weight and venous pressure varied concordantly, although the daily changes were not always concordant (Fig. 1, 2, and 3). The associated changes in sodium excretion were inversely related to those of weight and venous pressure. The patient whose weight and venous pressure were decreasing excreted the largest per cent of the injected Na²² during this period, while the least was excreted by the patient whose weight and venous pressure were increasing.

(2) Effect of adding sodium chloride to the, diet. Twelve grams of NaCl per day were added to the diet of the normal subject and the patient with congestive heart failure who was recovering (Patient No. 1). This resulted in a marked increase in the sodium clearance and in the sodium excretion of the normal subject, but there was only a slight increase in the clearance without an increase in the total Na²² excretion in the patient with heart failure. There was a slight increase in the weight and venous pressure associated with the decrease in total Na²² output in the patient with congestive heart failure.

Three distinct substances which differ in their relative specific gravities have been stratified by high centrifugal force in the Erythrocytes of man. These substances seem to differ chemically for they may be differentially stained by certain dyes. The stretching of certain of the erythrocytes by centrifugal force indicates that they possess a membrane of considerable elasticity.

Protein fractions of hog kidney, in themselves inactive on perfusion, become strongly vasoconstrictive when supplemented with traces of epinephrine. While a similar influence of minute quantities of epinephrine on vasoconstriction is well known to occur with some sympathomimetic amines, insufficient information is at hand to clarify the pharmacological nature of the observed synergistic action.

Many protein fractions isolated from kidney, liver and heart of hog, and from kidney and liver of dog and rabbit, inactive when perfused alone through the rabbit's ear, become vasoconstrictive at varying degrees when combined with subthreshold quantities of epinephrine.

In contrast, dialyzed saline extracts of fresh minced organs were inactive with and without addition of epinephrine. After freezing and thawing or prolonged dialyzation against distilled water epinephrine addition resulted in some activity. 0.8 mg of protein or protein mixture secured by continued fractionation of hog liver and combined with subthreshold amounts of epinephrine, produced marked and long lasting vasoconstrictions.

An apparatus is described for the rapid shell-freezing of fluids in small containers preparatory to drying from the frozen state (lyophilization).

Rats were given alcohol daily and either a high or low casein diet Control series received similar diets and no alcohol. The amount of food intake in control groups was regulated according to the amount taken by the rats receiving alcohol. The effect of total food intake in those receiving alcohol as compared with those not receiving alcohol was further observed by weight curves. Fatty infiltration of the liver occurred in every animal receiving alcohol and low casein diet, alcohol and high casein diet, and in all those receiving low casein diet and no alcohol. None of the animals receiving the same volume of the high casein diet and no alcohol had fatty infiltration of the liver. It is therefore concluded that alcohol exerts an effect which permits accumulation of fat within the liver cells, and that this effect operates separately from that of extrinsic deficiency of lipotropic factors.

The experiments presented above show that complement-fixing antibodies can be demonstrated in the blood of rats immunized with formalized Lansing virus, in convalescent monkey serum, and in some convalescent human sera when concentrated Lansing virus from cotton rats is used as antigen. The results with rat sera are complicated by the presence of antibodies against components of normal brain and spinal cord in both immune and normal animals, but the evidence indicates that the primary reaction with immune sera is between antibody and virus. Immunization as a result of injection of formalized virus is, therefore, associated with the production of serologically detectable antibodies to active virus. The experiments with the convalescent monkey and human sera provide definite proof that positive complement fixation can be demonstrated when concentrated Lansing virus prepared as described 2 is used as the antigen. These latter results further support the importance of the Lansing virus or an antigenically related strain as one responsible for the human disease.

Experiments are presented which show that (a) hyaluronidase increases the intensity of allergic skin inflammation of the epidermal type and (b) that antihistaminic substances such as Pyribenzamine and antistine counteract the spreading effect of India ink and hyaluronidase, as well as the atter's effect upon the allergic skin inflammation. The significance of these findings for the activity of antihistaminics in epidermal sensitizations is discussed.

A new technique for the isolation of the snake erythrocyte nuclei using tyrothricin as an hemolytic agent is described. Some properties and chemical data are reported. The desoxyribonucleic acid content of the erythrocyte nuclei for the 6 kinds of snakes studied was higher than that reported for chicken erythrocytes and liver rat nuclei.

The sporozoites of P. cathe-merium 3H2, an organism causing severe infections in canaries, were injected intramuscularly in large numbers into full-grown barnyard hens, In the respective trials the in-jectum consisted of (a) the gauze filtrate of infected mosquitoes ground in fresh hen plasma; (b) the gauze filtrate of infected mosquitoes ground in hen plasma obtained after allowing the drawn blood to stand for one hour at room temperature; (c) the gauze filtrate of infected mosquitoes ground in Locke's solution; (d) whole canary blood to which was added the gauze filtrate of infected mosquitoes ground in Locke's solution, the mixture being incubated at the temperature of hen blood for 2 1/2 hours before using for injection. None of the injected hens in any of the trials became infected and all of the canaries injected as controls did become infected.

Two human volunteers were bitten, respectively, by 11 and 17 mosquitoes infected with P. cathemerium 3H2; neither of the individuals became infected so far as could be determined by a study of peripheral blood smears and subinoculation of blood inta canaries.

Calcium penicillin in beeswax and peanut oil was employed to treat groups of rabbits infected with Tr. pallidum. The calculated total dose based on body weight was administered in 8 daily injections. A CD₅₀ of 1,070 units per kilo of body weight w^as observed. This value does not differ significantly from a CD₅₀ of 1,400 units per kilo reported by Fleming following administration of a similar preparation in 16 equal daily doses. It was concluded that when calcium penicillin in beeswax-peanut oil is employed in the treatment of rabbit syphilis, increasing the number of daily injections from 8 to 16 does not alter the total curative dose (CD₅₀).

1. Attempts to use dark field examinations of the lymph nodes of mice as proofs of syphilitic infection 45 and 90 days after inoculation have failed, using the method employed successfully by Kato.

2. This failure to find the Treponema pallidum in lymph nodes by Kato's method confirms Karrenberg's studies.

3. More exhaustive methods of searching for the treponeme, such as those of Van Haelst, appear to be necessary.

Many resports on canine hysteria have stressed the remarkable resemblance of this syndrome to human idiopathic epilepsy. The nervous disorder in dogs is characterized clinically by irregular “grand mal” seizures, “running fits,” ataxia, and “hysterical” states, with apparent recovery between attacks. The electro-encephalograms of these dogs show a cerebral dysrhythmia similar to that of human epilepsy. Because of these common features, it seems proper to term the condition canine epilepsy.

A dietary etiology of this disease has been proposed by various investigators, e.g., gliadin toxicity, 1 lysine deficiency from wheat flour diet 2 and wheat gluten flour toxicity. 3 , 4 This etiology is supported and explained by the crucial experiment of Mellanby. 5 He showed that the treatment of flour with agene gas, i.e., nitrogen trichloride (NCl₃), a process used on approximately 90% of the white wheat flour milled in both England and the United States, rendered that flour convulsant to dogs. The toxicity of the wheat fractions used in the investigations cited above was presumably due to agene treatment (NCl₃ treatment)† of the flour source, inasmuch as untreated wheat fractions showed no toxicity. The purposes of this communication are to describe a method of producing consistently and rapidly a convulsive disorder in dogs, and to delimit the toxic principle.

Method. A diet having a high flour component was prepared. The control ration, including supplementation with accessory food substances, and the actual analysis of this diet, is given below.

The diet, with water added, was baked into biscuits at 395 °F for 30 minutes. The biscuits were canned and pasteurized after sealing. The analysis shown in Table I was made of these biscuits 2 weeks after baking.

When an amino acid mixture approximating the composition of gliadin is treated with nitrogen trichloride gas (NCI₃) this mixture is so altered as to make it con-vulsant for dogs when given intravenously. The convulsant activity is most readily demonstrated in dogs which have been on a bleached (agenized) flour diet for 5 to 7 days, presumably because these animals have accumulated sufficient quantity of the toxic material via the alimentary tract, to make them highly susceptible to an additional increment received via the blood stream.

The presence of cortin-like activity in extracts of horse urine has been confirmed. It is estimated that the concentration of this active material is approximately the same in urine of normal horses and normal humans. There is some indication that urinary cortin-like activity is increased in pregnancy.

1. Studies were made to determine whether there is a difference in the weight and bacterial population of the cecal contents of mice of the C₅₇ and A strains, which were the same age and received the same diet.

2. The C₅₇ animals fed a synthetic diet (No. 101) had a significantly greater amount of cecal contents and bacterial count per cecum than the A strain mice of the same age and fed the same diet. Although most of the bacterial flora appeared to be the same in the 2 strains, a Gram-negative, anaerobic rod did occur more frequently in the C₅₇ mice than in the A strain.

3. There was no significant difference between the black and white mice of the same age fed the stock ration with respect to weight of cecal contents or bacterial count per cecum. The young black mice may have had a more diverse flora than the white mice of the same age.

4. It was postulated that this greater weight of cecal contents with its higher bacterial population in the C₅₇ mice might help to explain the lower B vitamin requirements of this strain when comparing it with animals of the A strain, both fed the same synthetic diet.

Isolated strips of rabbit intestine and rat and rabbit uteri respond with spasmolysis when treated with “dolophine” and demerol when spasm is induced with furmethide or Methergine. The ratio of spasmolytic concentration is approximately 1:1 although rabbit uteri required slightly more dolophine than demerol for spasmolysis.

Three cases are described from 4 experimental groups totaling 24 birds, some observed for more than 4 years, in which single comb brown Leghorn hens displayed male copulatory behavior following successive implants of testosterone propionate pellets. Implantations were begun when birds were 4 days, and 1, 3, and 5 months old. These results contrast with earlier negative findings following single daily injections of this hormone. Induction of copulatory behavior in such a small percentage of cases indicates the desirability for further study of factors controlling this behavior pattern.

Within the last 12 years the Indians of the Southwest have been investigated as to the occurrence of the various agglutinogens. Allen and Schaeffer 1 reported on the classic blood groups, and Allen and Larsen 2 reported their findings on the M and N agglutinogens. The basis of this report is the Rh factor among the above mentioned Indians.

The Indians tested were patients at the U. S. Indian Hospital and the Indian School Hospital at Albuquerque, New Mexico. Students of the Indian School at Albuquerque and the Day School at Isleta were also used in this study. The age range was from school age to 60 years.

Lederle's Anti-Rh Serum (Anti-Rh0) was used in this series of tests; this serum is of animal origin. Two drops of blood to be tested were added to 0.5 cc of physiological saline containing 1% sodium citrate. One drop of the cell suspension is placed on a clean glass slide. Next to this is placed one drop of Anti-Rh Serum. The two are mixed with a glass rod and finally by tilting the slide back and forth once. The slide is placed undisturbed on the table for 3 minutes. At the end of this time the slide is picked up and given 2 or 3 gentle turns.

1. Melanin granules were obtained by differential centrifugation from the S-91 and Harding-Passey transplantable mouse melanomas, from the choroid, ciliary body and iris of the beef eye, and from colored human skin. These preparations were characterized with teh electron microscope.

2. the melanin-containing pseudoglobulin from the S-91 melanoma was shown to consist of melanin granules unchanged in shape or size with respect to granules obtained by centrifugation.

The test proposed by Majovski et al. for evaluating the effects of vitamin P on capillaries was subjected to a critical study.

The experience of others that previous feeding affects the results of the test was confirmed, but this objection can be overcome by using starved mice only.

The present tests demonstrate that Majov-ski's method is non-specific, however, because a number of solvents used for the rutin, as well as other substances, gave mice the same protection against low atmospheric pressure as rutin did. The drugs which protected mice are not known to have any effect on capillaries; they were: propylene glycol, ethylene glycol, ethyl alcohol and glucose.

In experiments carried out on adult male white rats under sodium pentobarbital anaesthesia, intravenous administration of ketone bodies resulted in an increase in the glycogen stores of the heart. Concomitant increase in the glycogen stores of the liver and skeletal muscle did not occur.

The temporal relation between the contractions of the left and right heart chambers was studied by means of fluoro-cardiography and simultaneous recording of 2 pulse tracings on one strip. The study was performed on 8 normal subjects and included the observation of the pulsations of the aorta and the pulmonary artery, both auricles and both ventricles. In all observations the contraction of the right auricle preceded that of the left auricle and the contraction of the right ventricle that of the left. The delay of action of the left chambers was found to be between 25 and 30 milliseconds.

The incubation of mouse spontaneous carcinoma, rabbit Brown-Pearce carcinoma, and their autologous liver slices with bacterial cultures showed in general that cells of both liver and tumor were uninjured or injured equally. Cultures of Sporosarcina ureae damaged tumor cells and left liver cells histologically unaffected. Evidence was obtained that the selective carcinoclastic factor of S. ureae cultures was contained within the cells and released on autolysis.

We are indebted to Dr. C. B. van Niel of the Hopkins Marine Station for free access to the culture collection, to Colonel Max Levine for cultures of several of the Enterobaeteriaeeae, and to Dr. William Negherbon for cultures of trypanosomes and detailed directions for their maintenance.

Fifteen adult dogs furnish the basis for the observations which are to follow. The animals were kept in metabolism cages and given a diet of Purina Dog Chow. No restriction as to the amount was made in the diet or in the water intake. The dithiol was given intramuscularly at 9 a. m. and 9 p. m. on 4 successive days. The dogs were divided into 3 groups. The animals of Group I were given 5 mg per kilo of the dithiol per dose, those of Group II, 15 mg and the members of Group III, 30 mg per kilo. Prior to the commencement of the injections liver function studies were undertaken by the use of bromsulfalein according to the technique devised by Rosenthal and White. 1 For the normal animals and those of Group I, such observations have been satisfactory in that all of the dye was removed from the plasma within half an hour. In the animals of Group II and Group III receiving respectively 15 and 30 mg of dithiol per kilo the rate of removal was invariably prolonged beyond the half-hour period. The percentage removal however during this and subsequent periods was extremely variable. The evidence for the development of a liver injury from the dithiol is not confined to such variable functional observations but has been ascertained by obtaining biopsy material from the livers and by the study of such tissue in those animals that came to autopsy. The tissue was stained for lipoid material with Scharlach R and also with hematoxylin and eosin. A study of such material permits the following conclusions:

1. In the animals of Group I which received 5 mg of 2-3-dithiopropinol per kilo it was difficult if not impossible to ascertain by such a micro-chemical method whether or not there was any actual increase in lipoid material in the hepatic epithelium over that which can be frequently observed in such tissue designated as normal.

While the hypertension and nephrosclerosis produced in the rat b}^ anterior pituitary preparations are prevented by low- protein deits, the otherwise similar lesions induced by desoxycorticosterone overdosage are largely independent fo the dietary protein intak.

e are grateful to the Shering Corporation of New Jersey for desoxycortieosterone acetate and to Misses L. Derome and T. Hansen for technical assistance.

The effects of dithiobiuret on electrical activity of cortex were tested upon 4 cats, 2 dogs, and one rat. Normal animals or the same animals were used as controls. Twenty-two rats were used in chronic administration and 12 of these were used to determine cortical threshold to electrically induced convulsions. The significant findings were: (1) a lack of detectable electroence-phalographic change in cortical activity of animals tested after immediate or prolonged administration of dithiobiuret, (2) cortical threshold to electrically induced convulsions of rats was raised by an average of approximately 26 volts and (3) the form of convulsion in intoxicated rats was altered.

Conclusion. Dithiobiuret is an effective anti-convulsant in rats only when they are intoxicated. The site of action of ditbiobiuret is within the central nervous system; the most probable site is the efferent system of the spinal cord.

A case is reported with eczematous hypersensitivity restricted to alkyl esters of p-aminobenzoic acid. No reaction was obtained with substances deviating from this basic structure in the ring or in the side chain.

The β-diethylaminoethyl esters of di-α-thienyl-, diphenyl-, phenyl-a-thienyl-and cyclohexyl-α-thienylglycolic acids are anticholinergic drugs with significant mydriatic action. Of these, the cyclohexyl-α-thienylglycolic acid ester (No. 623) is the most mydriatic substance. The nitrate salt of this ester is very soluble in water and causes only small damage to sensitive tissues when used daily for several days at a concentration of 1.0 or 2.0%. It is suggested that this substance may have clinical applications as a mydriatic and cycloplegic agent.

The action of whole dried plasma and its primary fractions separated by low temperature-ethanol procedure on casein was investigated. No kinase was added and there was no previous treatment of the protein preparations with chloroform or any other agents. Proteolytic activity was demonstrated by determinations of acid soluble total nitrogen and “tyrosine.”

Human plasma Fraction I contains a high degree of proteolytic activity. The enzyme is inactivated at 80°C and functions at near neutrality.

When transplantable mouse sarcomas were infected experimentally with Cl. histolyticum, and the infection controlled by systemic injections of histolyticus antitoxin, the life span of some of the animals was prolonged for as long as 20 days beyond that of the non-infected tumor bearers. But in no instance did the infection completely destroy the tumor tissue. All surviving mice, treated eventually with penicillin in order to eradicate residual infection, developed large sarcomas. Under similar conditions, no such temporary regression was observed for transplantable mouse carcinomas.

When a study was made of the effect of histolyticus toxin on transplantable mouse tumors, it was found that systemic (intramuscular) injections of toxin were without effect, whereas repeated local injections of toxin, given either directly into the tumor mass or subeutaneously around the base of the tumor, resulted in marked regression of tumor tissue. But for the toxin preparations used, the effective dose approximated, very closely, the lethal dose, particularly when the toxin wras injected directly into the tumor mass. In no instance was there a permanent regression of the tumor.

In tissue culture, carcinoma cells were more resistant to the action of histolyticus toxin than sarcoma cells, just as normal epithelium seemed to be more resistant that stroma cells or fibroblasts. But normal and cancerous epithelium were equally resistant to concentrations of toxin that produced severe damage to sarcoma cells.

Evidence has been presented to indicate that dogs with the Thomas-type bile fistula are much more satisfactory than those with the Rous-MxM aster-type fistula for studies of liver function, particularly those involving collection and examination of bile. Data are presented regarding the normal biliary excretion of bromsulfalein following intravenous injection of 2 mg and 5 mg of the dye per kilogram of body weight.

The authors are indebted to Dr. J. Earl Thomas for advice and assistance in the preparation of the bile-fistula dogs used in these studies.

In 2 cases of solar urticaria the maximum sensitivity was found to be at 3131 Å. Studies of the photosensitizing agent in the patients' serum support the conception that this condition is due to sensitization to a physiological radiation product in the skin.

The ATP-ase activity of smooth muscle is found to be considerably higher than that of striated muscle. It is unaffected by dilute concentrations of chemical mediators. Fluoride apparently has an inhibitory effect. Variation in the ATP-ase activity of the uterus coould not be correlated with cyclical estrus change. With the possible exception of testosterone, hormones did not appear of affect the in vitro system.

1. Mature rats were maintained on a fat free diet for relatively long periods without showing any deficiency symptoms except emaciation.

2. Severe depletion followed by ad libitum feeding of the fat free diet precipitated in mature rats symptoms including those typical of essential fatty acid deficiency.

3. This method is suggested for other types of experiments where a “strain” on body functions is desired.

4. Either ethyl linoleate or corn oil prevented entirely or cured rapidly the symptoms of essential fatty acid deficiency when they appeared.

5. When the rats, after depletion, were maintained on the fat free diet ad libitum for sufficiently long periods, spontaneous disappearance of all the symptoms was observed, for which the explanation of some synthesis of essential fatty acid is suggested.

The rapid intravenous injection of gases or mineral oil in sufficient quantities to replace blood in the right ventricle of dogs will cause the reduction or loss of the initial ventricular deflection of the electrocardiogram in direct leads from the epicardial surface of the right ventricle.

Observations on a series of 80 normal male subjects, on a normal control diet, indicated an average daily urinary excretion of approximately 318 ± 9 mg of methionine. The increase in methionine excretion during the 6- and 24-hour periods following the ingestion of a 1.0 or 1.5 g supplement of methionine in addition to that of the usual protein intake only amounted to approximately 9 and 15% respectively of the intake of the free amino acid.

The ingestion for 4 days of diets of varying protein content showed no change in the daily urinary methionine excretion as a result of such variation. A decrease in the methionine normally excreted occurred when the subjects were on a high fat diet or when, on a 6-hour test, they were given a similar test supplement of methionine. Increased lipotropic requirements might account for the decrease in the loss of methionine after a 3-day fast or high fat intake.

The acoustical modification of the Skeggs and Leonards apparatus described facilitates determination of the blood pressure of rats but can be used only after vasodilatation produced by heat or drugs. Priscol produces vasodilatation sufficient for repeated blood pressure determination during a 9- or 10-hour period.

We wish to express appreciation to A. A. Foster for directing our attention to the electrical circuit herein described and to L. T, Skeggs and J. R. Leonards for one of their electrical end point devices.

Relaxin is found in the blood of guinea pigs on about the 21st day of pregnancy, at which time relaxation of the symphysis pubis may first be detected by palpation. The concentration of relaxin reaches a peak of 0.5 G.P. units per ml of blood serum on the 28th day and is maintained until the 63rd day when the concentration falls to 0.33 G.P. units per ml. Immediately after parturition a precipitous decline of the relax-in content of the blood serum takes place. The urine shows a concentration of 0.5 G.P. units of relaxin per ml at 42 and 56 days of pregnancy with a drop to 0.25 G.P. units by the 63rd day. The uterus contains about 10 G.P. units per gram of tissue on the 56th and 63rd day of pregnancy whereas the placenta shows 5 G.P. units per gram of tissue on the 56th day and 2.5 G.P. units on the 63rd day. It seems probable that the drop in serum relaxin in the latter part of pregnancy may be due to a decreased output from the placenta.

The earliest demonstrable effect of chorionic gonadotrophin on the ovary of rats is the appearance of hyperemia. 1 This reaction has been used with varying degrees of success for the rapid diagnosis of pregnancy. Attempts to enhance the effect of chorionic gonadotrophin on ovarian hyperemia led to our present use of a pituitary extract for this purpose. This was based on the well-known synergistic effect of certain anterior pituitary extracts in augmenting the ovarian response when used in conjunction with chorionic gonadotrophin. 2 The effective component of such pituitary extracts is not known. The earlier claims 3 that such “synergists” represent a distinct gonadotrophin no longer seems likely in view of later work 4 indicating that similar effects can be obtained with follicle-stimulating gonadotrophins (F.S.H.). The pituitary synergist† employed in these studies is reported to be chiefly F.S.H., with traces of luteinizing principle. 5 Prolactin was not demonstrable.

Methods and Results. The 28- to 32-day-old, 50 to 60 g immature albino female rats used were of a mixed strain of unknown identity. Chorionic gonadotrophin, the pituitary synergist, or their combination was injected intraperitoneally into a total of 307 rats. The rats were asphyxiated with ether and autopsied after one, 1 1/4 or 2 hours. The reaction was considered positive if one or both ovaries were light to dark crimson, and negative if both were pale or pinkish. The details of the technic used have been described by Kupperman and Greenblatt. 6

The results are given in Table I. There were no positive reactions with the synergist alone. Chorionic gonadotrophin in a dosage of 0.6 I.U. produced positive reactions in 76% of 25 rats.