Experimental Biology and Medicine

These results demonstrate that dogs can be fed a ration containing moderate levels (30%) of commercially agenized flour for long periods of time (12-14½ months) without developing running fits or electroencephalographic abnormalities.

1. Rats fed a 16% casein, 51% fat diet for 29 weeks all developed markedly fatty livers. Nearly all of the animals showed a diffuse, progressive hepatic fibrosis.

2. The fatty change and fibrosis were completely prevented by supplementing the high-fat diet with choline, or with crude liver extract.

3. The lipotropic effect of the liver extract is not due to an increase in protein intake resulting from a stimulation of appetite, and is not due to the small amount of choline present in the liver extract.

Splenectomized white rabbits showed no significant change in percentage of reticulocytes following oral and parenteral administration of either pteroylglutamic acid or of liver extract effective in pernicious anemia. Greater variations were found in daily reticulocyte counts, both in controls and in splenectomized animals, than were reported by Jacobson and Williams.

Two cases are described in which type N individuals produced anti-M agglutinins following injections at widely spaced intervals of blood containing the M agglutinogen. On the basis of these and other observations, it is pointed out that type N patients requiring a series of transfusions at wide intervals should be transfused only with type N blood, if isosensitization and consequent transfusion reactions are to be avoided. Genetic and serologic analogies among the A-B-O, M-N and Rh-Hr systems of blood factors are pointed out. Evidence is cited to show that the factors in each system fall naturally into two major subdivisions.

The lesions of ulcerative cecitis of rats resolved within 10 days of streptomycin treatment. The antibiotic was added to the animals' drinking water in an average dose of 0.1 g per day per rat. The bacilli of the Salmonella group which are invariably associated with the ulcers of cecitis were sensitive to streptomycin in the test tube and they could no longer be grown from the cecums of treated rats with healed lesions.

The length of survival of dogs having a low simple intestinal obstruction depends upon the ability to maintain fluid, electrolyte, and nutritional requirements. By parenteral alimentation with the methods used adequate nutritional requirements were not obtained, but in 1 animal in which these requirements were approached more closely the length of survival was 45 days.

Gastric mucin significantly enhances the virulence of tubercle bacilli for pigmented strains (dba, C3H or C57 black) of mice. Grossly visible lesions containing large numbers of tubercle bacilli are usually present 10 days after intraperitoneal inoculation with the dosages and strains of tubercle bacilli studied. Several isolations of tubercle bacilli from patients have been made 10 to 15 days after inoculation by use of pigmented mice (dba or C3H) and mucin.

Addendum. Recently the number of isolations from patients has been increased by feeding pigmented mice inoculated with mucin the cornmeal-gelatin-butter diet of Dubos and Pierce. 4

The identification of the cell within lymphatic tissue which produces antibody has been approached by the application of a new histochemical technic for localization of cytoplasmic ribonucleic acid. The latter has been found to be an invariable concomitant to the formation of new protein in tissue. In lymph nodes actively engaged in the production of antibodies a wide range of lymphocytes, largely younger forms, was found to have cytoplasmic granules and nucleoli stained with pyronine, which is used to identify ribonucleic acid. Such granules and nucleoli were found also in transitional forms between reticulum cells and lymphocytes, but in no other cell types.

A viscosimetric method is described for the study of the sickling tendency of red cells from subjects with sickle cell disease. This method does not differentiate between sickle cell anemia and sickle cell trait. Data are compared with observations of other investigators.

Recently, the complement fixation reaction in typhus fever, first studied by Castaneda, 1 has been refined so that not only typhus may be differentiated from other rickettsial diseases such as Rocky Mountain Spotted Fever, 2 but may itself be classified according to epidemic or murine nature. 3 Inasmuch as we have been interested in the etiology of typhus fever in this area, and have reached certain tentative conclusions based on the studies of the biology of the rickettsia strains locally isolated, 4 we wish now to use the complement fixation test to complete our studies. Unfortunately so far, owing to the scarcity of clinical cases seen in the past year, the number of sera examined has been small. But the results seem to be sufficiently consistent to warrant a preliminary report at this time.

Method and results. The antigens used in the present study, kindly supplied by the Lederle Laboratory Division of the American Cyanamid Company, 5 consist of washed rickettsial bodies. The method of complement fixation test is that of Kolmer's modified by reducing all ingredients to one-half the volume of the regular method. Sera were obtained from patients suffering from clinical typhus fever 6 some of which have been preserved by the lyophile process. Any serum showing anticomplementary action was treated by the method of Faran. 7 It was found that all except one gave positive reaction to both antigens, with titres mostly above 1:320, and one reaching as high as 1:20,480. Among these, 5 sera showed the same titre for both antigens, while 14 sera from 10 patients showed a higher titre to the epidemic antigen: 4 with a 2-fold difference, 4 with 4-fold difference, 5 with 8-fold difference and one positive only to epidemic antigen at titre 1:640.

The isometric relaxation period of the left ventricle in normal subjects and in patients with mitral stenosis was studied. This period was measured on the phonocardiogram as the interval between the main vibration of the second sound and the opening sound or snap of the mitral valve.

The findings in 7 normal subjects varied between 0.04 and 0.07 seconds; 24 mitral patients had figures of from 0.07 to 0.11 seconds. Additional data on the split second pulmonic sound and the third heart sound are presented.

Simultaneous phonocardiograms and fluorocardiograms in a normal subject and in a patient with mitral stenosis, both having an opening sound or snap of the mitral valve, allowed correlation of the ventricular fluorocardiogram with the sound tracing in regard to the isometric relaxation period.

A strain of staphylococci in becoming resistant to penicillin did not show an increase in its resistance to sulfactin. A similar strain of staphylococci in becoming resistant to sulfactin did not show an increase in its resistance to penicillin. The increase in resistance to sulfactin developed by the strain of staphylococci was intermediate between the increment in resistance developed by staphylococci to penicillin and the increase in resistance developed by a strain of E. coli to streptomycin.

Quantitative analysis of the adrenal glands of the wild Norway rat reveals that the total fats comprise 6.5% of the gland and that of this 3.7% are cholesterols. These figures are lower than the values for the adrenal gland of the domestic rat. However, since the cortex of the adrenal gland of the wild rat is 2-3 times larger than that of the domestic rat, the wild rat has much more cholesterol available for hormone production.

Complement fixation tests for murine typhus were performed upon the sera of 203 persons who, it is highly probable, had suffered an attack of murine typhus 7 days to 3 years and 11 months previously. The tests were positive in 85 to 88% of the cases, and in most instances the positive titers were high. Among 201 persons suspected of having had typhus, though the diagnosis was not conclusively established, the per cent of positive reactions was less, but the titers of positive sera did not differ significantly from those of the group in which the diagnosis was considered to be established. Up to periods of 4 years after infection, mean positive titers at yearly intervals did not suggest a pronounced loss of titer with passage of time. With the exception of infrequent reactions at 1:2 dilutions in the sera of persons who had not had typhus, the test was found to be specific.

Determinations of phosphor-us-containing compounds of the whole brain tissue taken from normal mice and from mice suffering from polio-encephalitis produced by the MM poliomyelitis virus did not reveal any significant differences in the inorganic, acid soluble, lipid, nucleic acid, “protein residue” or total phosphorus fractions. Nor did they show any significant differences in the desoxyribosenucleic acid content as determined by the diphenylamine reaction. However, the content of ribosenueleic acid as determined by the orcinol-HCl reaction was significantly reduced in infected brains as compared with normal mouse brain tissue.

Female rabbits were inseminated with semen diluted with Krebs solution at rates of 1/1000 up to 1/5000 and 0.2 cc of suspension were used. The number of spermatozoa effective for partial fertility was 16,000, and for maximum fertility was around 90,000. The group percentage of fertility resulting from vaginal insemination was slightly higher than from uterine insemination (50% vs 40%); this difference was not of statistical significance.

When semen samples were diluted from 1:100 up to 1:12800, the motility of the spermatozoa decreased significantly as the rates of dilution increased and the average motility shown in Krebs solution and the maximal dilution that would support motility was significantly higher than in 0.9% sodium chloride solution.

When females were inseminated with a small number of spermatozoa (20,000) suspended in different volumes of Krebs solution, the average percentages of fertility were higher in the smaller volumes. The motility of the spermatozoa, however, appeared to have a greater effect on the fertility than the dilution.

A number of synthetic nucleosides, and chloro- and bromo- derivatives of these nucleosides, were tested for growth-promoting and growth-inhibiting properties on Escherichia coli, strain 9723, and its uracil-re-quiring mutant, E. coli, strain 550-460; Neuro-spora crassa, wild strain Abbott 4A, and a uracil-less strain of Neurospora crassa, No. 1298; and on the growth of Lactobacillus casei and Streptococcus faecalis R.

The compounds tested were the 1-D-ribosyl-, 1-D-arabinosyl-, 1-D-glucosyl-, and 1-D-galactosyl- nucleosides of uracil, thymine, 5-chlorouracil and of 5-bromouracil. Of these 16 compounds, only a few at high concentrations showed inhibitory properties on the growth of the microorganisms tested. Some showed slight, but insignificant, growth-stimulatory activity.

The authors wish to show their appreciation to Miss Ann Coblenz, Miss Janet Tozer, Miss Evelyn Wyatt, and Mrs. Charmion McMillan for carrying out some of the microbiological tests.

Alkaline phosphatase in the rabbit appendix is almost as well preserved by fixation in chilled acetone as by the freezing drying technic. Acid phosphatase on the other hand is distinctly better preserved by dehydration in the frozen state than after acetone fixation. Acid phosphatase activities are maximal when determined promptly on fresh homogenates. Frozen tissues dehydrated in the frozen state and stored dry at −20°C gave acid phosphatase activities equal to 85% of fresh values and for homogenates stored at 5°C for 24-96 hours the values of fresh and frozen preparations were identical. Acetone and alcohol fixation gave marked reduction in acid phosphatase activity. Alkaline phosphatase activity of fresh tissue is reduced to about 75% of the fresh value by treatment with acetone or absolute alcohol at room temperature. The effects of temperature of fixation, storage in the dry state and embedding in paraffin are noted.

A technic for examining throat swabs which appears to have certain advantages is described. This method involves suspending the material on the swab in broth, inoculating blood agar plates with this suspension, and examining the resultant growth with the aid of a microscope. The experiments which led to the adoption of this technic are presented.

This and other similar technics for determining pharyngeal flora, however, have definite limitations, as indicated by the observation that inoculation of blood agar plates with a mixture of only two bacterial species yielded colonies which were not distributed at random on the surface of the medium, but rather in a manner indicating interdependence of the organisms. Thus, the growth on a plate does not necessarily reflect the relative proportion of each species present in the inoculum.

The value of selective media as a means of detecting organisms present in low frequency has been demonstrated by utilizing Pike's medium for the isolation of beta-hemolytic streptococci. The carrier rate for beta-hemolytic streptococci was increased from 9.6%, as determined by usual cultural methods, to 20.8% by the use of Pike's method. The increase was greatest for Group B streptococci and least for the typable strains of Group A.

Adrenocorticotropic hormone produced an increased ketonemia in a fasted normal dog.

1. A method for obtaining weekly bone marrow samples of adult rats is presented. 2. The bone marrow obtained from the iliac bone is essentially the same as has been obtained from the femur by previous investigators.

Mean values for inulin and PAH clearances and PAH tubular maxima corrected for surface area in premature infants ranged from 17 to 58% of normal adult values. Greater postnatal age appears to increase the rate of development of kidney function in premature infants weighing between 2100 and 2500 g although to a less extent than might be expected in full term infants.

The present series of papers deals with studies on strains of the virus of foot-and-mouth disease from outbreaks in Mexico. The work was undertaken at the request of the Bureau of Animal Industry of the United States Department of Agriculture on behalf of a joint Mexican-American Commission to whom all the results recorded here have been reported.∗

During the experiments recourse has been made to many new methods that have been developed at this institute, to which some preliminary reference should perhaps be made. The necessity of having a quantitative appreciation of a biological problem is becoming increasingly apparent especially in approaching problems of immunity. No great reliance can be placed on the results of “field” vaccination experiments, for example, in estimating the real value of an immunizing agent as it is not possible to analyse satisfactorily the many factors involved. This can be done only under controlled experimental conditions. Again before satisfactory interpretations can be made of the results of experiments carried out under controlled conditions it is necessary to have reliable “standard methods.”

The main program of the scientific staff of this Institute for the last eight years has been directed with this object in view. As a result it is now possible to measure the potency of virus suspensions of bovine origin such as are used for vaccine production by a method of titration involving the simultaneous inoculation of a number of serial dilutions of virus in the bovine tongue. 1 Sufficient observations are made for the calculation of the 50% end-point. This method guarantees the greatest accuracy commensurate with the use of a very limited number of animals.

In serum neutralization tests correlated with electrophoretic studies and the development of methods for concentrating antibodies it has been shown that by application of the above titration method it is possible to estimate with a greater degree of accuracy than was formerly attainable, the neutralizing and protective properties of bovine antisera and to detect low levels of antibody. 2 For quantitative estimates of this sort it is obvious that there must be basic information on the relative susceptibility of the test animals employed. In the case of foot-and-mouth disease where cattle are the experimental animals of choice for the study of virus of bovine origin, this susceptibility must vary within wide limits according to the source.

These observations were made during the examination of samples of virus which were recovered from cattle during an epizootic in Mexico. It was reported that foot-and-mouth disease existed in Mexico in the last quarter of 1946 and now in June, 1948, fresh outbreaks of the disease are still occurring. Up to the present 13 separate samples of virus from Mexico have been examined at this Institute and as will be seen from the results recorded all of them could be classified in the main Vallée A immunological type group. After identification these virus samples were termed strains of the virus of foot-and-mouth disease. For the purpose of future reference a list is appended with the dates of collection and reported geographical origin:

MP-Puebla, Dec. 23, 1946

MPB-Puebla, Jan. 1, 1947

MC-Camarones, Jan. 21

MSL-San Lorenzo, Jan. 31

M.1-Jalisco, Oct. 7

M.2-Cuerrero, Oct. 11

M.3-Toluca, Sept. 20

M.4-Lerma, Sept. 30

M.5-El Sal to, Jalisco, Nov.

M.6-El Bajo, Jalisco, Mar. 19, 1948

M.7-Guzman, Apr. 12

M.8-Zapotiltic, Apr. 13

M.9-Zapotiltic, Apr. 13

So far the antigenic behavior of only 2 of the virus strains MP (23.12.46) and M.l (7.10.47) have been investigated in some detail but further work is proceeding on the Mexican strains of virus and the results will be reported later.

These studies on antigenicity which are reported in other papers of the present series include complement fixation, serum neutralization and vaccination experiments.

Identification of infective agent and general immunological type classification.

1. Animal Species Susceptibility.

(a) Inoculation of cattle.

The respective inoculation of suspensions of the thirteen samples of material received intradermally into the tongues of cattle has produced in every case a generalized vesicular disease resembling, in its general characteristics, foot-and-mouth disease.

(b) Inoculation of horses and donkeys. Suspensions of some of the samples of material received were inoculated intradermally into the tongues of horses and donkeys as follows:

M.l-2 horses and 2 donkeys

M.2-2 horses

M.3-2 horses

M.4-2 donkeys

MP-2 donkeys and contrary to what might have happened if the virus of vesicular stomatitis had been involved, no lesions were observed in any instance.

A report on the identification of samples of virus received from Mexico has been made. 1

Before referring to the general effects of the Mexican strains of virus in cattle exposed to infection by inoculation, by contact with diseased cattle, or by the nasal instillation of virus, something should be said about the animals employed in these experiments.

Foot-and-mouth disease is not endemic in Great Britain but is introduced at irregular intervals, outbreaks occurring sporadically. Since the policy of control is by “stamping-out,” that is, elimination of infected and “in-contact” animals by slaughter and burning (or under the exigencies of war, by burial) along with the rigorous application of other disinfection and “stand-still” orders, it is possible only to purchase cattle with a “clean” history as regards foot-and-mouth disease. The cattle used in these experiments were Devon steers between V/2. and 2 years old, in good condition and weighing between 600-800 lbs, and they could be considered as relatively “standard.”

1. Intradermal inoculation Into the tongue. In all 296 cattle have been inoculated with centrifuged suspensions or stock filtrates of the 13 strains of Mexican virus. 184 were inoculated with MP virus, 80 with M.l virus, and the remaining 32 with the other 11 strains. 293 of these 296 reacted well, with local lesions at the sites of inoculation and generalized or secondary lesions at some or all of the usual sites of predilection, feet, and lips, in all cases except 2. These 2 were control animals inoculated with filtrates in an experiment described elsewhere. 2

There were 3 cattle which failed to show lesions at the sites of inoculation. These had been inoculated with similar virus material to that which had produced the disease in other cattle. One of these however subsequently developed lesions at sites other than those inoculated, probably resulting from infection by contact with its box companion which had reacted. The other 2 developed local lesions on the tongue when re-inoculated with the Pirbright stock cattle strain 119 of the Vallée A type.

Two strains of the virus of foot-and-mouth disease, of Vallée A type, have been found to differ antigenically from each other and from the stock strain of this type used in this Institute.

(1) Differences between strains of the virus of foot-and-mouth disease of one type have been demonstrated by cross-neutralization tests in cattle. (2) The magnitude of such differences in these experiments is not so great as that between immunological types.

The low invasiveness of the Mexican strains of virus used in the vaccination experiments described with the resultant incomplete reaction of the control groups of cattle made the interpretation of the results difficult. Nevertheless 88 of a total of 96 cattle i.e. 92% which had received a dose of 100 cc of blood vaccine (with crystal violet added), in which the method of inactivation of the virus is by incubation at 37°C, showed no lesions in contact tests or no secondary lesions in tongue inoculation tests when the challenge strain or strains of virus (bivalent vaccines) were those used for preparing the vaccine. Even if all tests are included i.e. tests in which the doses of vaccine were 100 cc or only 30 cc or 25 cc or the challenge Mexican strain of virus was not the same as that used for vaccine production 110 of 136 i.e. 81% showed equivalent protection. This compared with the 12 of 56 i.e. 21% of non-vaccinated control cattle which remained free of all lesions in contact tests and secondary lesions in tongue inoculation tests.

BAL in a dose of 0.2 mM/kg given 3 times weekly fails to prevent, cure, or materially alter cobalt-induced polycythemia in rats. The general toxicity of BAL appears minimal when given in this dosage over a 3½-month period.

During the course of comparative tissue culture studies of a strain of normal rat fibroblasts and its malignant cell derivative, 1 we obtained preparations of both of these cell types which under the electron microscope† showed an unmistakable fibrillar structure in the thinly spread cytoplasm. The fibrils, of an estimated thickness of 10 to 100 mμ, may converge and diverge in fan-like formations of great regularity (Fig. 1) but are more often seen gathered together in long bands of varying widths (Fig. 2). The composite bands are seen clearly in phase microscope movies of the cells, 3 but it is only by the increased resolution available with the electron microscope that the nature of the bands becomes clear. They are apparently composed of long thin converging fibrils which in general radiate from the dense central area. That the fibrils are not produced by a wrinkling of the formvar membrane on which the cell is stretched is indicated by their uniformity, by their sharp change in direction in certain areas of the periphery, and by their fine converging and diverging structure. Besides this, no wrinkles were seen in the membrane outside of the cellular area where clear visualization is possible.

Of interest are the relations of these bands to the general structure. The mitochondria, often long and thin, seem frequently to be associated with individual fat droplets. Some of the elongated mitochondria are found in areas which show many microsomes, with the whole area bounded by parallel fibrous bands. This appears to be a static representation of the streams of material which can be seen in the movies of these cells. In other areas, the great masses of mitochondria may be seen crossing those fibrous bands.

Brilliant cresyl blue and certain other basic dyes, if applied to fluid blood, bring out a reticulum in young red blood cells. This reticulum fails to appear if brilliant cresyl blue or other basic dyes are applied to dried and alcohol fixed blood smears. Moreover, no reticular structure could hitherto be demonstrated in the young red blood cells by microscopic examination of unstained blood with direct or oblique illumination, dark field illumination or in ultraviolet light. 1

While examining unstained wet blood films of albino mice with the phase microscope, we found that an occasional red blood cell showed a very delicate, hardly discernible reticulum. The cells showing this reticulum were fewer in number than the reticulocytes demonstrable by supravital staining with brilliant cresyl blue. However, when certain hypotonic salt solutions, preferably potassium oxalate 0.8% or ammonium oxalate 1.2% were mixed with the fresh blood, a larger number of cells, corresponding to the percentage of reticulocytes, showed distinct granules and short rods within their cytoplasm.

Most of these rods and granules showed prominent Brownian movement. In such preparation, varying number of cells showed marked loss of hemoglobin. Granules predominated in hemolyzed cells, while rods were more prominent in cells containing ample hemoglobin. The percentage of cells showing rods or granules was higher in those areas of the preparation in which hemolysis was marked. Smears, dried and fixed in alcohol, failed to show these cytoplasmic structures. However, dried but unfixed smears, if mounted in 10% formalin or 1.2% ammonium oxalate, (Fig. 1), showed rods and granules resembling those seen in the fresh preparations. Also, fixation of dried smears in 3% aqueous potassium dichromate did not interfere with the demonstration of the rods and granules. It is noteworthy that both formalin and dichromate applied to the dried smear hemolyzed the red blood cells.

The influence of interrupted carcinogenic treatment on tumor formation was tested. Rest periods of from one to 3 months were interspersed between 2 periods during which the carcinogens were applied to mice at minimal carcinogenic levels. The investigation was divided into two parts on the basis of the carcinogens employed. In one, ultraviolet irradiation was used for both the first and second periods. In the other, methylcholanthrene was employed to initiate the process and croton oil, a non-carcinogenic substance, was used to evoke the neoplasms. The results with both technics were essentially the same.

A lag in tumor appearance was observed during the rest periods, and the second period of treatment quickly brought forth tumors in the precarcinogenic areas. Essentially no difference in the rate of tumor formation or in the final tumor incidence was observed when the rest period was of one month duration. When the rest period was increased to 3 months, the final tumor incidence was reduced by 34% in the mice irradiated and by 42% in those in the methylcholanthrene-croton oil series. The results indicate that the initial application of the carcinogen produced alterations in the tissues which were maintained for at least one month, thereafter the changes reverted toward normal. It is suggested that the genesis of the neoplastic cell was completed during the initial treatment, and such cells remained dormant or divided at a decreased rate until further stimulated. The non-specific irritant, croton oil, exerts its effect during the critical period of carcinogenesis.

Three Inaba strains of V. comma isolated recently in Egypt harbored fractions of Salmonella I, XII and g antigens.

Under the experimental conditions employed, rutin does not antagonize dicoumarolism in rats. Presumably the defect in the vessel walls or their supporting structures which leads to hemorrhage in dicoumnrolism differs from that leading to the various hemorrhagic conditions which rutin and related “vitamin P”-like substances purportedly benefit. These facts, however, need not necessarily preclude the simultaneous use of dicoumarol and “vitamin P” for their separate effects, as illustrated by the report of MacLean and Brabel 17 on the favorable effects of rutin and dicoumarol in various retinal vascular disorders.

The virus of mumps was isolated from the blood of a patient with bilateral parotid swelling through culture in embryo-nated eggs. Inhibition of hemagglutination and complement fixation tests confirmed the clinical diagnosis and identified the agent as the mumps virus.

Quantitative limitation of food intake sufficient to account for average body-weight differences of 55% between underfed and litter-mate control rats, has also resulted in statistically significant differences in myelination of the optic tracts and nerves. The concentration of myelin in the optic tracts of the underfed rats has averaged 20% less than that in the control animals. Since myelination of the optic tracts, as shown by spectrophotometric determinations in litter-mate rats at successively older ages, is not complete until sometime between the 40th and 50th days, the conclusion seems justified that the relative lack of myelin observed in the underfed animals is due to partial or complete arrest of the process of myelination.

1. The therapeutic effect of streptomycin was evaluated in mice infected with a pneumotropic pasteurella either by the respiratory or by the intracerebral route.

2. When treatment was started within 4 hours after infection intracerebrally mice could be saved by streptomycin injected subcutaneously. With a total dose of 0.3 g/kg streptomycin the main factor determining success of therapy was the time interval between infection and first administration of antibiotic.

3. With comparable dosage regimens larger amounts of streptomycin were necessary to cure the intracerebral than the respiratory infection.

4. When treatment of the pulmonary infection was delayed for 18 hours, until symptoms and lesions were present, marked differences appeared in the effectiveness of dosage schedules similar in their effects when treatment was started soon after infection.

5. The possible usefulness of “natural” type infections in chemotherapeutic experiments is discussed and compared to the “test-tube” type of experimental disease.

The intragastric administration of an extract of pregnant mares' urine, Kutrol, in quantities as large as 7.50 g does not decrease the volume, free acidity, or output of hydrochloric acid in the 12-hour nocturnal gastric secretion or in the continuous 36-hour secretion of patients with peptic ulcer.

1. Twelve records of the effect of a deep, forced expiration on finger pulse volume were obtained from six subjects. In four of these records a ballistocardiogram was recorded simultaneously. In 5 other tracings total finger volume changes were recorded.

2. In all cases the pulse volume and total finger volume (when recorded) decreased immediately following the deep forced expiration. Average duration of diminution was 16 seconds for pulse volume and 24 seconds for total finger volume.

3. The absence of a simultaneous decrease in corresponding ballistocardiogram beats suggests that the observed finger changes were due to reflex arteriolar constriction, possibly initiated by abdominal presso-receptors in the great veins or mesentery.

The frequent failure to obtain infarcts and the variability in the size of the infarcts which follow ligation of a coronary artery in the dog suggest the presence of prominent anastomotic communications with collateral vascular beds. To determine whether these communications were in deep or superficial vessels, the consistency of infarction with simple coronary ligation was compared with the infarction which resulted from coronary ligation plus occlusion of the superficial vessels by cauterization about the cognate bed of the ligated vessels. Since the latter procedure produced infarctions of predictable size in all of the 17 dogs so treated, which survived for 24 hours or longer, it is concluded that the principal anastomotic communications with collateral vessels lie in the epicardium.

It is suggested that ligation plus superficial cauterization may be of definite value in providing a fairly well standardized procedure for the experimental study of myocardial infarction.

Growth hormone at a dose level of 200 γ per day reduces the urinary nitrogen excretion of fasting adult female rats.

The relationship of the × zone of the mouse adrenal 1 , 2 , 3 to the pituitary is not known. It was considered that the use of the technic of hypophysectomy might produce results of help in the elucidation of this problem.

Material and Methods. Virgin female “Swiss albino” mice, aged 40-42 days at the commencement of the experiment, were used. The adrenal × zone is well developed at this age. Hypophysectomy was performed by the parapharyngeal approach. Injection of the hormones noted below was started 24 hours after the operation (except that the chorionic gonadotropin injections were commenced 48 hours after operation) and the animals killed 24 hours after the last injection. The mice were grouped as follows:

1. Twelve intact untreated animals killed at 54-58 days of age.

2. Eleven animals hypophysectomised for 12 days and 8 for 14 days and then killed.

3. Nine hypophysectomised animals injected with a pituitary preparation, principally adrenocorticotropin+ in nature, 1 mg per day divided into three intraperitoneal in jections, for 12 days.

4. Nine hypophysectomised animals injected subcutaneously with 1 mg of pituitary gonadotropin, principally LH†† in nature, for 10 days.

5. Five hypophysectomised animals injected subcutaneously with 1 mg per day of pituitary gonadotropin, principally FSH in nature, for 10 days.

6. Six hypophysectomised animals injected intraperitoneally with 11 LU of human chorionic gonadotropin (“Korotrin”) per day for 10 days.

The right adrenal was treated routinely after fixation in Bouin's and stained in Harris' haemotoxylin and eosin or Heidenhain's Azan, The left adrenals were fixed for histochemical studies and are not being reported upon here. The thymus, uterus and ovaries were weighed; the ovaries were then treated as for the right adrenal. The completeness of hypophysectomy was judged by the examination of serial sections of the appropriate area in 2 cases from each group; in the remainder the success of the operation was judged by the examination of the sella turcica region under binoculars (x 15). Added confirmation was given by the weight of the animal and, where relevant, by the weights of the uterus and ovaries and the histological condition of the ovaries and adrenals.

Immature female rats failed to survive when fed purified rations containing both pancreas and desiccated thyroid. Length of survival was significantly prolonged if either pancreas or thyroid were eliminated from the experimental ration. The deleterious effects of pancreas in the thyroid-fed rat were not due to increased digestion or absorption of thyroactive material.

1. An egg-adapted strain of mumps virus has been cultivated in suspended cell tissue cultures. 2. In such media the mumps virus as well as Influenza A virus (PR8 strain) produce measurable quantities of hemagglutinin.

Sexually mature rats maintained on a magnesium-deficient diet develop lesions of the skin characterized by erythema, purpural hemorrhages and eschars. The addition of magnesium to the diet results in recovery from the skin lesions. Other symptoms observed are essentially the same as in the immature animal deprived of magnesium. The increased length of time before the appearance of symptoms in older animals probably reflects increased body stores of magnesium with an increment in the time required to deplete the tissues of this element.

Aminophyllin was given in a single intravenous injection to a group of 18 patients, and orally 4 times daily for a week to a second group of 12 subjects.

There were no statistically significant changes in the clotting time of the blood or in the undiluted or 12.5% (diluted) plasma prothrombin times following the administration of aminophyllin.

1. No inhibition of tumors was noted in Bagg-albino strain mice with spontaneous mammary carcinoma over one cm in size when treated with whole culture lysate of T. cruzi; on the other hand in the same mouse strain with tumors under one cm in size a degree of inhibition was noted which warrants closer study.

2. The inhibition noted could not be attributed to malnutrition effects or concurrent bacterial infections.

3. No inhibition was noted in tumor-bearing “A” strain mice (spontaneous mammary carcinoma; transplanted carcinoma No. 119) when treated with T. cruzi whole culture lysates.

4. Survival time of treated tumor-bearing mice was less than that of control treated animals.

5. A simple method is given for a reproducible preparation of T. cruzi lysates.

1. The virus which is the causative agent of infectious fibroma, giving rise to tumor-like nodules in rabbits, was maintained by serial passage on the chorioallantoic membrane of the embryonated hen's egg for 18 consecutive passages.

2. The titer of virus in infected chorioallantoic tissue was slightly lower than the titer in rabbit tissues. It was maintained by using eggs incubated for 11 days prior to inoculation and making passages at 3-day intervals.

3. Invasion of the embryo and extra-embryonic fluids did not take place in eggs inoculated on the choriallantoic membrane. Inoculation of the virus into the allantoic sac, the amniotic sac, the yolk sac and the embryo itself yielded negative results.

4. Although marked edema of the chorioallantoic membrane was noted in some of the infected, no pathognomonic lesion, gross or microscopic, was present, so that it was necessary in every instance to resort to back passage into rabbits to demonstrate the presence of virus.

5. The type of lesion produced in rabbits by the virus was not significantly altered by repeated passage in hen's eggs.

In 8 dogs studied both before and after operation, cholecystectomy produced no significant change in the daily excretion of fat or nitrogen in the feces.

The dilute alcohol extract of the coptis root has been demonstrated to have a definite and fairly high antibacterial action against a number of both Gram positive and Gram negative bacteria. Its lethal dose for albino rats has been found to be more than 250 mg per kg body weight.

The author wishes to express his deep gratitude to Professor Samuel H. Zia for his constant advice and helpful criticisms during this investigation.

1. The anticoagulant effect of dicumarol at various prothrombin levels in dogs has been studied.

2. In control animals thrombosis occurred, on the average, in 6.3 minutes, with a variation from 3 to 10 minutes.

3. In dicumarolized dogs the time of thrombosis was not delayed at prothrombin levels above 40%. Below 40% thrombosis occurred on the average, in 16.6 minutes.

1. The phenomenon of tachyphylaxis of the intestinal musculature to morphine was demonstrated.

2. The most consistent reponse of the circular muscle of the duodenum to morphine was an increase in the many phases of muscular activity. This includes elevation of the tonus level with incerased frequency and amplitude of the normal spontaneous tonic contractions.

3. The most frequent though not completely consistent reponse of the lingitudinal muscle was found to be either a decrease or an abolition of the many phases of the muscle activity. This includes a depression of the tonus level with a decreased frequency and amplitude of the normal spontaneous tonic contractions.

4. The type of response of the duodenum to morphine was independent of the original state of tonus and independent of the dose over the range of 0.01 mg to 1.0 mg per kg.

A hemorrhage of 30 cc/kg proved fatal in 93% of the cases. Pretreatment with Dibenamine reduced this mortality to 10%. Pulse rate and blood flow per second were consistently greater in the second series. Administration of 80 blows/kg to each hind leg with a light mallet produced fatal shock in 100% of the cases. Pretreatment with Dibenamine reduced the mortality to 11%. Control animals showed vasoconstriction, treated animals vasodilation.

1. In 92 unselected clearance periods in 29 tests on 22 patients 100.4 mg of mannitol were recovered in the urine for every 100 mg injected.

2. In 30 periods in 16 tests on 12 patients selected on the basis of plasma equilibrium and technical adequacy 99.3 mg of mannitol were recovered for every 100 mg injected.

3. These data reveal no significant extrarenal disposal of mannitol.

1. In the same patient with duodenal ulcer the 12-hour nocturnal gastric secretion is usually unaltered with healing of the ulcer.

2. The average 12-hour nocturnal gastric secretion of patients with active ulcer is not significantly different than in patients with healed duodenal ulcer.

3. Twelve-hour nocturnal gastric secretion in patients with healed duodenal ulcer and who are without symptoms is significantly greater than that of normal healthy individuals.

Gonadotrophic hormones from a castrated male cross successfully the first parabiotic union to stimulate the ovaries of the middle female of a set of triple parabiont rats. But the gonadotrophins are so completely utilized by the center animal that they produce no detectable ovarian stimulation of the second female.

Rats hypophysectomized and castrated on day 26 and injected immediately thereafter with 0.1 mg testosterone propionate daily for 21 days showed an average daily weight gain of 1g. During the same period unoperated, uninjected littermate controls gained approximately 5g daily. The distal segment of the penis of these experimental animals weighed on an average 25% more than the normal 47-day-old controls. The ossicle in this portion of the penis of the experimental group measured 3.80 ± 0.12 mm as contrasted with the normal length of 4.1 ± 0.2 mm and the original length of 3.33 ± 0.15 mm for the 26-day-old normal and the length of 3.20 ± 0.18 mm for the doubly-operated 47-day-old controls uninjected with hormone.

Animals reared on a diet deficient in an essential amino acid (tryptophan, phenylalanine) showed a reduced incorporation of tracer amounts of C¹⁴ from labeled amino acids in the tissue proteins.

The method of local passive sensitization so extensively employed in human allergy (Prausnitz-Küstner reaction) and in experimental anaphylaxis (Opie and others), can also be applied to the cellular transfer of tuberculin hypersensitivity discovered by Chase. 3 Compared with the latter's experimental procedure, this method offers the advantage of considerably reducing the number of cell donors necessary for successful transfer. The technic used is, however, susceptible of improvement, as in the presence of a marked primary reaction of cavy skin to the injection of homologous exudate cells none but fairly strong tuberculin reactions can be recorded with confidence.

The action of acetylcholine, histamine, physostigmine, neostigmine, and hexaethyltetraphosphate was studied on the isolated ileum of the guinea pig, rabbit, rat and chicken in non-atropinized and atropinized media. In all 4 species the contractions caused by acetylcholine and histamine reinforced each other immediately after the death of the animal, regardless of the order in which they were added to the bath. Two and a half hours to 3 hours after death, histamine failed to contract the intestine when it was added at the height of an acetylcholine contraction. In the rat, rabbit and chicken the intestine no longer responded to histamine at a time when it still reacted to acetylcholine and to the cholinesterase inhibitors. In all 4 species atropine failed to block the action of acetylcholine and cholinesterase inhibitors in intestinal strips which were at least 3 hours old.

1. Renal plasma flow was studied by the para-amino-hippurate clearance method during moderate exercise of relatively long duration in 4 healthy young men. 2. During the first 16 minutes of walking 3 m.p.h. at 5% grade the renal plasma flow fell from 9 to 23.2% (of the resting control); during the second 16 minute period it fell from 15.4 to 36.6% and during the third 16 minute period from 18.5 to 33.7%. 3. During the second and third hours of exercise (2 consecutive 56-minute periods), there was little further change in the renal plasma flow. 4. In 2 of 3 experiments where recovery was studied, the renal plasma flow had returned to within 10% of the resting control value one hour after cessation of exercise.

The lumbar spines of 30 young rabbits were unilaterally irradiated with radon seeds and X-rays. Twenty-one animals died of gastro-intestinal disturbances unrelated to radiation. Five of the 9 survivors showed wedging of the vertebral bodies with the narrowing of the bodies on the more heavily irradiated side. Dosage estimates indicate that growth of the epiphyses of the vertebral bodies of baby rabbits may be suppressed with 700 to 1000 r to the epiphysis. Doses of 350 r or less have no apparent effect on the growth.

After a single oral dose of 0.5 or 0.75 g of aureomycin given to fasting normal subjects antibiotic activity was recovered in the urine for more than 33 to 55 hours. The antibiotic was excreted in high concentrations between 2 and 16 hours and the largest rate of excretion occurred between 2 and 8 hours. The findings suggest that the optimum intervals between oral doses of aureomycin should be about 8 hours.

The stereotaxic technique has been applied to the human brain for relief of mental disorders with a prevalent emotional component and of intractable pain. In epileptics suffering from grand and petit mal, the electrothalamogram was recorded, revealing spike discharges; lesions placed in the vicinity of the commissura media diminished frequency and severity of the petit mal attacks.

In 14 clinical cases involving uremic syndrome herein reported upon, it was found that:

a) The free phenols had little if any effect in producing or intensifying the uremic syndrome, b) During the uremic syndrome the free, conjugated and total phenols did increase, but not significantly enough to warrant their consideration as an important factor in the uremic syndrome. The methods employed in previous reports give reason to doubt the validity of conclusions drawn concerning the relationship of free, conjugated and total phenols to the uremic syndrome.

This preliminary study, utilizing recently developed fluorimetric technics together with standard biological procedures, indicates that the eggs of the American lobster at the time of attachment to the caudal appendage contain estrogenic activity estimated at a minimum of 100 international units per 100 g of eggs. That a substantially increased yield may be affected by further refinements in extraction methods is now being investigated.

1. A quantitative method for the determination of estradiol, estrone and estriol in urine, based on the fluorescence of these substances when treated with phosphoric acid, is described. 2. The method is more accurate, sensitive and specific than other known biological or colorimetric tests. 3. The recoveries of estradiol were above 80%; of estrone between 70 and 80%; and of estriol between 50 and 60%. The mean experimental error was ± 10%. 4. The described method permits the determination of estriol in urine in quantities not hitherto detectable.

When tested by the sensitive isotopic method, neither an aqueous extract of nodules nor a purified preparation of hemoprotein could induce fixation of atmospheric nitrogen by free-living Rhizobium.

Cultures of the root nodule bacteria taken directly from the nodules and tested prior to cultivation on laboratory media did not fix nitrogen even though hemoprotein was present.

In a few experiments, fixation of molecular nitrogen was obtained, but the nodular preparations were shown to contain nitrogen-fixing Clostridia.

Specific lipid fractions fo certain animal sera appear capable of inactivating psittacosis virus in vitro though the original sear exerts no such effect. The virus inactivating property appears to be in the lecithin-like and cephalin-like fractions, and peculiar to serum lipids.