THE OCCURRENCE OF BACILLUS INFLUENZ? IN THE NORMAL THROAT

1. The frequency of occurrence of Baculus influenzœ in the throats of normal individuals has been as great in the period subsequent to the epidemic of influenza as it was during the period of the epidemic. 2. Bacillus influenzœ may persist in the throats of healthy carriers for a considerable period of time. 3. A considerable proportion of individuals not exposed during the epidemic has been found to carry Bacillus influenzœ in their throats. 4. Oleate hemoglobin agar has been found to be a very satisfactory selective medium for cultivation of Bacillus influenzœ from the throat. To give optimum results it should have a reaction of from pH 7.2 to 7.5.     

STUDIES ON THE BIOLOGY OF STREPTOCOCCUS : IV. THE OCCURRENCE OF STREPTOCOCCUS SCARLATIN? IN CONVALESCENCE AND IN THE COMPLICATIONS OF SCARLET FEVER.

1. A group of streptococci which agglutinate with scarlatinal immune sera has been isolated from the throats of 65 per cent of cases of scarlet fever during the 1st week of the disease. 2. Strains of hemolytic streptococci belonging to this group have been isolated from the throats of patients at the termination of quarantine (30 days). 3. Hemolytic streptococci are found most frequently in the throat in convalescent patients in whom the tonsillar inflammation has not entirely subsided. 4. The complications occurring in scarlet fever may be due to the original scarlatinal strain or may be the result of a secondary infection with pyogenic strains of streptococci.     

CHANGES IN THE SHAPE AND SIZE OF BACTERIUM COLI AND BACILLUS MEGATHERIUM UNDER THE INFLUENCE OF BACTERIOPHAGE—A MOTION PHOTOMICROGRAPHIC ANALYSIS OF THE MECHANISM OF LYSIS

This paper contains the records of a motion photomicrographic investigation of the lysis of Bact. coli and B. megatherium by bacteriophage. The bacteria mixed with bacteriophage were grown on moist nutrient agar in small culture chambers on the stage of a microscope in an incubator maintained at 37°C. The apparatus used permitted continuous inspection of the preparations. Photographs were made at the rates of 2 and 30 per minute and at the rate of 8 per second during the terminal stage of lysis of Bact. coli. The accurately timed films were studied by rapid projection and by the projection of single frames. Measurements of dimensions of cells, calculations of volumes, information on generations, generation times and duration spans are presented in the tables. Similar information on normal cultures grown and photographed in the same way is furnished for comparison. Groups of serial photographs are reproduced in the plates to illustrate the special features observed. These observations seem to us to warrant the following conclusions: 1. Enlargement or swelling of the cells of Bact. coli usually, but not always, precedes lysis. Some of the enlargement is an expression of increase of cell substance and is not altogether due to imbibition of water. Cells of early generations of Bact. coli enlarge to greater absolute and relative proportions than cells of later generations. Enlargement does not occur before lysis in B. megatherium. 2. The terminal stage of lysis of Bact. coli is explosive, occupying ½ to ⅞ second. The terminal stage of lysis of B. megatherium is a slow disintegrative process, extending over 2–10 minutes. 3. Bacteriophage inhibits fission of some cells, but does not stop the reproduction of other cells in contact with it. The genealogical records of six generations of cells of Bact. coli and of two generations of cells of B. megatherium indicate that bacteriophage may be transmitted through parents to the offspring which ultimately undergo lysis. 4. Bacteriophage spreads by contact through a group of cells and also along paths determined by genetical relationships. 5. A large amount of cellular debris remains after the lysis of the cells in both of these species of bacteria. This residue of material is in the form of irregularly shaped masses and granules. This material is not in solution at the time of lysis and appears not to be digested or hydrolized. 6. Theories of the mechanism of lysis are discussed. It is suggested that reduction of surface tension of the cells may be an important factor in the mechanism of lysis.     

THE GERMICIDAL ACTION OF α-MERCAPTO AND α-DISULFO SOAPS

1. Certain of the α-mercapto soaps and α-disulfo soaps are powerful germicides. 2. In the α-mercapto series, those soaps with 12 and 14 carbon atoms are most germicidal. In the disulfo series, the dicaprate, dilaurate, and dimyristate are most germicidal. The optimum number of carbon atoms varies with the test organism used. 3. These soaps, like others previously studied, show a markedly selective germicidal action.     

EXPERIMENTS ON THE EPIDEMIOLOGY OF PSEUDORABIES : II. PREVALENCE OF THE DISEASE AMONG MIDDLE WESTERN SWINE AND THE POSSIBLE R?LE OF RATS IN HERD-TO-HERD INFECTIONS

Study of the pseudorabies virus-neutralizing antibody content of pooled and individual samples of swine serum have led to the conclusion that pseudorabies is a highly prevalent, unrecognized, disease in middle western hogs. It has been shown that wild brown rats develop a fatal infection following ingestion of pseudorabies virus and that their carcasses, in turn, give rise to the disease in swine to which they are fed. It is believed that rats play a rôle in the epidemiology of porcine pseudorabies, serving as the initial source of infection for a swine herd and also as one means by which virus can be spread from farm to farm in swine herds. The experiments presented furnish further evidence that swine may serve as the source of infection for cattle.     

THE GERMICIDAL AND HEMOLYTIC ACTION OF α-BROM SOAPS

1. The soaps of the α-brom fatty acids are usually more germicidal than the unsubstituted soaps. Only when B. typhosus was the test organism was there no increase in germicidal action. 2. For any test organism, germicidal action of the brominated soaps increases rapidly with increasing molecular weight up to a certain point, then diminishes. This is likewise true of the hemolytic titer. The point of maximal germicidal action varies with the different species of tests organisms. In the series studied, brominated soaps of 12 and 14 carbon atoms were most germicidal for the Gram-negative organisms, while soaps of 16 and 18 carbon atoms were most germicidal for Gram-positive organisms. 3. The brominated soaps are, in general, more active in acid that in neutral or alkaline reactions. The reasons for this have been discussed in a previous paper, in which a similar phenomenon with unsubstituted soaps was observed. 4. For certain organisms, the brominated soaps are among the most rapid and potent germicides known.     

STUDIES ON THE MECHANISM OF IMMUNITY IN TUBERCULOSIS : THE R?LE OF EXTRACELLULAR FACTORS AND LOCAL IMMUNITY IN THE FIXATION AND INHIBITION OF GROWTH OF TUBERCLE BACILLI

1. The fate of bacilli of reinfection at the portal of entry and in metastatic foci, and also the associated host responses, are essentially similar in rabbits and guinea pigs. 2. However, in the guinea pig tubercle bacilli of reinfection are more effectively fixed at the portal of entry than in the rabbit. 3. The guinea pig fixes at the site of reinfection unrelated substances, such as trypan blue and agar particles, more effectively than the rabbit. 4. At the site of a local non-specific inflammation precipitins from the circulating blood accumulate in higher concentration in tuberculous guinea pigs than in tuberculous rabbits. 5. These differing fixing capacities of the two species are associated with differences of extracellular character in the inflammation resulting from reinfection. (a) In the guinea pig, whose tissues are highly sensitized and greatly injured by the tubercle bacillus, the lymphatics adjoining the site of reinfection become thrombosed. In the rabbit whose tissues are moderately sensitized and less injured by the tubercle bacillus the corresponding lymphatics remain open. (b) In the guinea pig the fibrinous network at the site of inflammation forms a fine sieve-like structure. In the rabbit this network forms a coarse sieve-like barrier. 6. In rabbits and guinea pigs primarily infected, the destruction of tubercle bacilli takes place first and most extensively at the portal of entry. At this time they are less effectively destroyed in the nearest metastatic foci. Simultaneously they are still growing without hinderance in such foci in remote internal organs. 7. The cell-free body fluids of normal animals support the growth of tubercle bacilli in vivo. The body fluids of tuberculous animals under the same conditions are bacteriostatic for this microorganism. 8. Tubercle bacilli often multiply by preliminary subdivision into non-acid-fast granules, from which the acid-fast rods sprout. This confirms the work of Kahn.     

THE FACTORS CONCERNED IN THE APPEARANCE OF NUCLEATED RED BLOOD CORPUSCLES IN THE PERIPHERAL BLOOD : II. INFLUENCE OF PROCEDURES DESIGNED TO INCREASE THE RATE OF BLOOD FLOW THROUGH THE BLOOD-FORMING ORGANS—HEMORRHAGE AND INFUSION.

1. Hemorrhage with immediate saline infusion causes the appearance in the peripheral blood of a slightly increased number of normoblasts provided normoblasts are already present in the blood stream. Marrow hyperplasia does not intensify this reaction and the cells found probably do not leave the marrow pulp but are in the blood stream at the time of the experiment. 2. The slight increase in cells occurring immediately after hemorrhage and infusion is designated a pseudocrisis. True crises are much more extensive; they tend to occur just before rapid increase in the erythrocyte count and usually towards the end of the 1st week following hemorrhage. 3. Red cells and white cells tend to move from the marrow together, but this association is not invariable. 4. After repeated hemorrhages regeneration occurs independently of the appearance of nucleated red cells in the peripheral blood. 5. Repeated hemorrhages associated with extension of erythrocyteproducing marrow lead to polycythemia but not to a conspicuous increase in speed of regeneration.     

THE FREQUENCY OF BACILLUS INFLUENZ? IN THE NOSE AND THROAT IN ACUTE LOBAR PNEUMONIA

1. Bacillus influenza is frequently found in association with lobar pneumonia. 2. In lobar pneumonia both Bacillus influenza and pneumococcus are frequently found in the nose. 3. The influenza bacilli found in the upper respiratory tract of cases of lobar pneumonia are of various types. 4. The exact significance of these findings is at the present time not clear.     

THE FACTORS CONCERNED IN THE APPEARANCE OF NUCLEATED RED BLOOD CORPUSCLES IN THE PERIPHERAL BLOOD : I. INFLUENCE OF PROCEDURES DESIGNED TO INCREASE THE RATE OF BLOOD FLOW THROUGH THE BLOOD-FORMING ORGANS—EXERCISE AND NERVE SECTION.

1. Increase in circulatory rate caused by hard exercise has no power to dislocate nucleated red cells from the bone marrow either in normal, in anemic, in hyperplastic, or in anemic and hyperplastic animals. 2. In anemic and hyperplastic animals pseudocrises of nucleated red cells can be produced at certain periods by hard exercise, but careful analysis leads inevitably to the conclusion that the increase in these cells is merely a more accurate expression of circulatory content at the time of the procedure. 3. Section of the vasomotor nerves to the four limbs with consequent dilatation of the marrow vessels and increased blood flow through the tissue does not result in the freeing of nucleated red cells from the bone marrow.     

ON THE APPEARANCE OF CERTAIN AM?BOID BODIES IN THE BLOOD OF VACCINATED MONKEYS (RHOESUS) AND CHILDREN,AND IN THE BLOOD FROM CASES OF VARIOLA : AN EXPERIMENTAL STUDY.

1. The claim of L. Pfeiffer that small granular amœboid bodies are present in the blood of vaccinated children and calves, and in the blood from cases of variola, during the stage of fever is confirmed. A nucleus has not been positively made out in any of these bodies. 2. Granular amœboid bodies, having a diameter about one-third that of a red blood cell, appear, also, in the blood of the monkey during the active stage of vaccinia and disappear with the decline of the local inflammation. 3. A body of like appearance, granulation and size may occasionally be found in the normal blood of monkeys and children. 4. Pale amœboid bodies, containing a few dark pigment-like granules, are present in the blood from cases of variola and in the blood of the variolated monkey. Bodies of like appearance may occasionally be found in the blood of vaccinated children and monkeys.     

THE R?LE OF THE RETICULO-ENDOTHELIAL SYSTEM IN IMMUNITY : III. THE PRODUCTION OF ACTIVE AND PASSIVE ANAPHYLAXIS IN THE BLOCKED ANIMAL.

1. Guinea pigs injected intravenously with massive doses of India ink before active sensitization exhibited occasionally a more or less marked, decreased sensitiveness to the reinjection of the antigen. 2. The serum of rabbits which had received massive doses of India ink before the sensitizing injections, showed approximately the same titer of anaphylactic antibodies as that of sensitized normal control animals, as demonstrated by the degree of passive sensitization induced in guinea pigs. 3. The precipitin titer of sensitized rabbits blocked with massive doses of India ink was somewhat lower than that of sensitized normal controls. In one instance, the intravenous injection of smaller doses of India ink was followed by a higher precipitin titer. No uniform relation was found between the height of the precipitin titer and the anaphylactic power of the antiserums. 4. One blocking injection of India ink given to guinea pigs before passive sensitization did not interfere with the occurrence of anaphylactic shock nor alter its nature.     

ETIOLOGY OF OROYA FEVER : XII. INFLUENCE OF MALARIAL INFECTION (PLASMODIUM INUI?), SPLENECTOMY,OR BOTH,UPON EXPERIMENTAL CARRION'S DISEASE IN MONKEYS.

The experiments reported were designed to determine the influence of malarial infection (Plasmodium inui?), splenectomy, or both combined, upon the course and character of experimental infection with Bartonella bacilliformis in monkeys (Macacus rhesus and M. cynomolgus). Blood withdrawn from a monkey showing spontaneous malarial infection was inoculated intravenously into monkeys (a) 1 month prior to inoculation with virulent verruga material, (b) simultaneously with the verruga material, and (c) during convalescence from verruga infection of moderate severity. All the monkeys contracted the malarial infection and suffered one to three paroxysms during a period of about a month. The verruga lesions appeared in the inoculated animals in due course, were of average size, remained for the usual length of time, and Bartonella bacilliformis was recovered in culture from blood which also contained the plasmodia. The lesions in the convalescent animals continued to heal at the normal rate, and blood cultures were negative for Bartonella bacilliformis, as is usual during convalescence. One of the recovering animals was reinoculated with virulent verruga material a month after the injection of the malarial blood, but neither did new lesions arise nor old ones recur. The malarial infection, therefore, had no effect upon the course of verruga or upon the establishment of immunity to Pattonella bacilliformis, hence it would appear that malaria and verruga may coexist in the same individual without unfavorable effect of one disease upon the course of the other. Similarly, splenectomy led to no appreciable aggravation of Bartonella infection. One monkey subjected to splenectomy and inoculated with verruga material shortly afterwards had an unusually severe reaction, but another, which was infected with material from the first and simultaneously splenectomized, reacted only moderately, while the non-splenectomized control showed a severer type of cutaneous infection. Even the combination of splenectomy and malarial infection did not appreciably aggravate the experimental verruga. Neither relapse of verruga nor reinfection with Bartonella bacilliformis was induced in convalescent or recovered monkeys as a result of splenectomy.     

THE USE OF THE FINAL HYDROGEN ION CONCENTRATION IN DIFFERENTIATION OF STREPTOCOCCUS H?MOLYTICUS OF HUMAN AND BOVINE TYPES

1. Under the conditions of these experiments, there appears to be a distinct and constant difference in the final hydrogen ion concentration of Streptococcus hæmolyticus from human and bovine sources. 2. Of 124 strains of Streptococcus hæmolyticus from known human origin, 116 reached a final hydrogen ion concentration of from pH 5.0 to 5.3. Only 8 reached a pH more acid than 5.0 and none more acid than pH 4.8. 3. Of 45 strains of Streptococcus hæmolyticus from bovine sources, including 26 strains isolated from milk and the udder of cows, and 19 from cream cheese, 40 reached a final hydrogen ion concentration of pH 4.3 to 4.5. Of the remaining 5 which reached a pH of 5.0 to 5.2, two were of known human type and three of uncertain diagnosis. 4. A rapid and practical application of this method is proposed as a presumptive test in the differentiation of human and bovine types of Streptococcus hæmolyticus.     

THE R?LE OF THE RETICULO-ENDOTHELIAL SYSTEM IN IMMUNITY : VI. THE EFFECT OF ENDOTHELIAL BLOCKADE ON THE STORAGE AND DISTRIBUTION OF NEOARSPHENAMINE

1. Blockade of the reticulo-endothelial system by means of a single injection of India ink caused a marked retention of neoarsphenamine in the blood of guinea pigs during the first twenty minutes of observation after intravenous injection, as contrasted with the rapid disappearance of the drug from the blood of normal controls. 2. Rabbits blocked by a single dose of India ink showed a slower elimination of the drug from the circulation following the first few hours after intravenous injection than corresponding controls. 3. The arsenic content of the liver of mice, which received neoarsphenamine intravenously after a preceding blocking injection with India ink, was appreciably lower than the arsenic content of the normal organ under similar experimental conditions.     

PATHOLOGY OF THE EXPERIMENTAL PNEUMONIAS IN MICE FOLLOWING INHALATION OF STREPTOCOCCUS H?MOLYTICUS,OF FRIEDL?NDER'S BACILLUS,AND OF PNEUMOCOCCUS

1. Pulmonary consolidation may be produced in normal mice by the inhalation of Friedländer''s bacillus or Streptococcus hæmolylicus. 2. The initial lesion is in both instances interstitial in character and the spread is by way of the interstitial tissue, though the ultimate consolidation may come to resemble in the gross a lobar pneumonia. 3. The lesions grossly and microscopically may be distinguished from the lobar consolidation associated with pneumococcus infection of the lung. 4. Friedländer''s bacillus and Streptococcus hæmolyticus give rise to pneumonia in mice previously normal, whereas the pneumococcus produces pulmonary lesions only under special circumstances, as when the animals are alcoholized after partial immunization.     

THE R?LE OF THE THYROID IN THE REGULATION OF THE BLOOD CHOLESTEROL OF RABBITS

1. The blood cholesterol of rabbits on a normal diet without added cholesterol is increased only slightly (19 per cent) by thyroidectomy. 2. In rabbits with a hypercholesterolemia due to long continued cholesterol feeding, thyroidectomy causes a marked rise (137 per cent) in the blood cholesterol. This rise is usually maintained. 3. When long continued cholesterol feeding has failed to cause a rise in the blood cholesterol of rabbits, thyroidectomy abolishes this resistance and a hypercholesterolemia is promptly produced. 4. A single injection of thyroxin causes a significant drop in the blood cholesterol of rabbits with hypercholesterolemia. This reaction is not influenced by thyroidectomy. 5. Potassium iodide causes an increase in the blood cholesterol of rabbits with hypercholesterolemia. This reaction is not influenced by thyroidectomy in contrast to the effect of KI in preventing a rise in blood cholesterol when given concurrently from the beginning of cholesterol feeding, an effect which is abolished by thyroidectomy. It is suggested that two different mechanisms are involved. 6. A single injection of insulin produces a fall in the blood cholesterol of rabbits with hypercholesterolemia. If anything, thyroidectomy increases the magnitude of this effect.