STUDIES ON EXPERIMENTAL PNEUMONIA : X. PATHOLOGY OF EXPERIMENTAL INFLUENZA AND OF BACILLUS INFLUENZ? PNEUMONIA IN MONKEYS.

1. Virulent influenza bacilli, when injected into the nose and throat of monkeys (Cebus capucinus and Macacus syrichtus), excite an acute inflammation of the upper respiratory tract, characterized by swelling and hyperemia of the mucous membrane, infiltration of the mucosa and subrnucosa with leucocytes, desquamation of epithelial cells, and the production of a mucopurulent exudate. The accessory sinuses are often implicated in the infection. 2. Experimental Bacillus influenzæ infections of the upper respiratory tract are frequently accompanied or followed by bronchiolitis, peribronchial infiltration, and bronchopneumonia with hemorrhage and edema in the early stage, emphysema and bronchiectasis in the later stages. In general, the process closely resembles uncomplicated Bacillus influenzæ pneumonia in man. 3. The injection of virulent influenza bacilli directly into the trachea of monkeys induces in them an experimental bronchiolitis and hemorrhagic bronchopneumonia, similar in all respects to spontaneous Bacillus influenzæ pneumonia. 4. In experimental Bacillus influenzæinfections of either the upper or lower respiratory tract the influenza bacillus can usually be recovered during .the acute stage by culture, either pure or in association with other bacteria. 5. In experimental Bacillus influenzæ infections in monkeys characteristic changes occur in the thymus gland—hyperplasia of the follicles, distention of the lymphatic channels, and infiltration of the parenchyma with leucocytes. This enlargement appears to be merely part of a general hyperplasia of the lymphoid structures in the cervical and thoracic regions.     

STUDIES ON EXPERIMENTAL PNEUMONIA : VIII. EXPERIMENTAL STREPTOCOCCUS H?MOLYTICUS PNEUMONIA IN MONKEYS.

1. Pneumonia has been consistently produced in normal monkeys by intratracheal injection of Streptococcus hæmolyticus. 2. The pneumonia produced has been shown to be comparable with hemolytic streptococcus pneumonia in man with respect to its clinical features, complications, and pathology. 3. Two pathologic types of the disease have occurred, interstitial pneumonia and confluent lobular pneumonia. Both types have been found in the same animal. 4. The type of pneumonia has appeared to be dependent upon the amount of streptococcus culture injected, interstitial pneumonia following the injection of small amounts and being an expression of considerable resistance, confluent lobular pneumonia following the injection of large amounts and being an expression of comparative lack of resistance. 5. Study of the distribution of streptococci in the lungs and of the character of the lesions in early stages of the disease has shown that streptococci may primarily invade the pulmonary tissue by penetration of the walls of the larger bronchial branches and that they are distributed from the points of invasion by way of the peribronchial, perivascular, and septal interstitial tissue and lymphatics. Infection of the alveoli is likewise primarily an interstitial invasion of the alveolar walls by streptococci. 6. In one experiment it was found that preliminary injury to the respiratory tract by gassing with chlorine and that lowering of resistance by a preceding intraperitoneal injection of Bacillus influenza without local injury to the respiratory tract greatly facilitated invasion of the lungs by Streptococcus hæmolyticus. 7. A normal monkey inoculated in the nose and throat with Streptococcus hæmolyticus failed to develop pneumonia and showed no evidence of infection of the upper respiratory tract.     

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.     

STUDIES ON THE MECHANISM OF RECOVERY IN PNEUMONIA DUE TO FRIEDL?NDER'S BACILLUS : I. THE PATHOGENESIS OF EXPERIMENTAL FRIEDL?NDER'S BACILLUS PNEUMONIA

Experimental pneumonia due to Friedländer''s bacillus was produced in white rats by the intrabronchial inoculation of the bacilli suspended in mucin. The pneumonia was lobar in type, was almost uniformly fatal, and simulated the acute form of the natural disease in human beings. The pathogenesis of the pneumonic lesion was studied by examination of microscopic sections of the lungs of animals killed at frequent intervals during the course of the infection. The histologic characteristics of the various stages of the pneumonia were essentially the same as those previously described in experimental pneumococcal (Type I) pneumonia except for the following differences: (1) In isolated areas of the lung in Friedländer''s pneumonia many more bacteria were encountered in the alveoli than were ever noted in experimental pneumococcal pneumonia. (2) Abscess formation was common in the late stages of Friedländer''s infection, whereas it was not noted in the pneumococcal lesion. (3) Organization of the alveolar exudate, rarely observed in experimental pneumococcal pneumonia, was a prominent feature of the pneumonia due to Friedländer''s bacillus. The mechanism of spread of Friedländer''s lesion appeared to be the same as that of pneumococcal pneumonia. Likewise there was noted the same phagocytosis of organisms in the lungs of even bacteremic animals dying of the infection.     

STUDIES ON BACTERIAL NUTRITION : I. GROWTH OF BACILLUS INFLUENZ? IN HEMOGLOBIN-FREE MEDIA.

From the data presented in the foregoing experiments it is evident that Bacillus influenzæ will grow in a fluid medium consisting of plain broth to which have been added small amounts of emulsions or extracts of mucoid bacilli or of Bacillus proteus. The bacterial extracts may be made by simple boiling of the bacillary emulsions in broth or saline solution and centrifuging out the bacterial bodies; they may be filtered without losing their growth-inducing property. Cultures of Bacillus influenzæ in bacterial extract broth, if not too small doses of the extracts were employed, always showed heavier growth than the control cultures in blood broth, and growth occurred at a considerably earlier period than in blood broth. In many instances growth could be seen after 3 to 4 hours, and a bacterial whirl was always visible after 6 hours incubation. When the nature of the culture used for seeding is not stated, this was 0.1 cc. of the supernatant fluid of a blood broth culture. All cultures were made in fluid medium; solid medium is much more difficult to use in connection with the extracts. In explanation of the remarkable growth of Bacillus influenzæ in this blood-free medium, the idea is proposed that the growth-stimulating effect of the bacterial extracts is due possibly to substances of the same nature as the so called vitamines. Further investigations on this principle of bacterial nutrition will appear in subsequent papers, together with a more thorough study of the sources and character of the growth-inducing substances.     

STUDIES ON THE MECHANISM OF RECOVERY IN PNEUMONIA DUE TO FRIEDL?NDER'S BACILLUS : II. THE EFFECT OF SULFONAMIDE CHEMOTHERAPY UPON THE PULMONARY LESION OF EXPERIMENTAL FRIEDL?NDER'S BACILLUS PNEUMONIA

Sulfonamide chemotherapy was found to cure rats of an otherwise fatal form of experimental Friedländer''s bacillus pneumonia when treatment was begun 6 hours after inoculation. Most of the pneumonic lesions cleared completely, but an occasional animal exhibited small residual abscesses in the previously consolidated lung. The recovery process taking place in the lungs was studied histologically at various intervals during therapy. As in the case of pneumococcal pneumonia, the principal action of the sulfonamide was upon the bacteria in the advancing edema zone at the periphery of the pneumonic lesion. The bacteriostatic action of the drug appeared to stop the spread of the pneumonia, and the Friedländer bacilli were ultimately ingested and destroyed by the phagocytic cells in the alveolar exudate. The phagocytosis of bacteria in the lung was shown to be unrelated to the presence of antibody in the blood.     

STUDIES UPON EXPERIMENTAL PNEUMONIA IN RABBITS : V. THE R?LE OF THE LEUCOCYTE IN EXPERIMENTAL PNEUMONIA. THE RELATION OF THE NUMBER OF ORGANISMS INJECTED TO THE MORTALITY.

1. The importance of the leucocyte in the resistance of animals to experimental pneumonia is emphasized by the fact that animals treated with benzol, a leucotoxic substance, rapidly succumb to the disease, while animals treated in like manner with toluol, a very similar chemical substance causing no leucopenia, show no decreased resistance. 2. The rôle of the leucocyte in the resistance of animals to experimental pneumonia is further emphasized by the fact that animals that respond to the pneumococcus infection with a leucocytosis, as occurs after the repeated injection of toluol, are more resistant to the pneumonia. Further, the hyperleucocytosis produced by repeated injection of nutrose before the production of pneumonia likewise seems to increase the resistance of the animals. 3. Experimental pneumonia is not necessarily fatal in rabbits. The factors determining the outcome of the disease are numerous; among these is the number of bacteria inoculated. Animals receiving small doses usually survive, while those receiving comparatively large numbers usually succumb.     

STUDIES OF HYPERTHYROIDISM : III. BILE PIGMENT PRODUCTION AND ERYTHROCYTE DESTRUCTION IN THYROID-TREATED AMPHIBIAN LARV?.

Experimental hyperthyroidism in urodele larvæ (Amblystoma) and anuran larvæ (Rana, Bufo, and Hyla) is accompanied by definite changes in bile color. The normal pale green, or pale yellow-green, color of the full gall bladder changes progressively after thyroid administration to a brighter green, then emerald-green, and finally a very dark green. In several hundred observations no exceptions were noted. The bile pigment, biliverdin (and its derivatives), is elaborated from the hemoglobin of worn out erythrocytes. Thyroid administration induces an increased rate of erythrocyte destruction, and this is followed by an increased output of bile pigment. Other minor factors are mentioned which may to a limited extent modify the color of the bile. Erythrocyte destruction occurs largely by enucleation, cytoplasmic segmentation, and fragmentation, and is probably widespread in the body. Many fragments and senile red cells collect in the liver. During the later stages of thyroid treatment the macrophages become conspicuously active. They are especially abundant in the liver, the gut, and the gills. In addition to the hemoglobin eliminated after transformation into bile pigment, some is transported by macrophages through the gut lining, and to a less extent through the involuting gill epithelium, and thus eliminated from the body.     

STUDIES ON THE BIOLOGY OF STREPTOCOCCUS : III. AGGLUTINATION AND ABSORPTION OF AGGLUTININ WITH STREPTOCOCCUS SCARLATIN?.

1. Strains of hemolytic streptococci from cases of scarlet fever occurring in New York, San Francisco, Chicago, Baltimore, and Copenhagen, Denmark, all interagglutinate with immune sera prepared with these strains. 2. Sera prepared with these strains do not agglutinate pyogenic streptococci or strains isolated from cases of septic sore throat. 3. The strains obtained from the throats of patients from an epidemic of scarlet fever and the strain from the milk responsible for this epidemic fall into the scarlatinal group according to these agglutination tests. 4. Absorption tests can be carried out with these strains and sera under proper conditions. 5. A group of hemolytic streptococci biologically distinct from streptococci from other sources than scarlet fever is constantly associated with scarlatina. They constitute a group of closely related streptococci which may be identified by agglutination tests.     

STUDIES ON BACTERIAL NUTRITION : III. PLANT TISSUE,AS A SOURCE OF GROWTH ACCESSORY SUBSTANCES,IN THE CULTIVATION OF BACILLUS INTLUENZ?.

1. Growth of Bacillus infiuenzœ depends on two distinct and separable substances. 2. These growth accessory substances are present in blood. 3. They occur in plant as well as in animal tissue. 4. Sterile, raw potato will serve as a substitute for blood in the cultivation of Bacillus influenzœ.     

ETIOLOGY OF YELLOW FEVER : XIII. BEHAVIOR OF THE HEART IN THE EXPERIMENTAL INFECTION OF GUINEA PIGS AND MONKEYS WITH LEPTOSPIRA ICTEROIDES AND LEPTOSPIRA ICTEROH?MORRHAGI?.

1. Slowing of the heart occurred in monkeys and guinea pigs during the febrile period of the experimental infection due to Leptospira icteroides. A similar reaction took place in animals inoculated with Leptospira icterohœmorrhagiœ. 2. The mechanism of slowing was usually due to slowing of the whole heart. 3. Once incomplete heart block was seen. Changes in the ventricular complex occurred four times.     

STUDIES ON THE BACTERIOPHAGE OF D'HéRELLE : X. TOXIN PRODUCTION BY NORMAL AND BY PHAGE-RESISTANT SHIGA DYSENTERY BACILLI.

1. The production of exotoxin and of endotoxin by normal Shiga dysentery bacilli and by strains resistant to Laudman phage was found to be the same. 2. The presence of phage did not alter toxin production by the resistant organism.     

STUDIES ON THE MECHANISM OF RECOVERY IN PNEUMONIA DUE TO FRIEDL?DER'S BACILLUS : III. THE R?LE OF "SURFACE PHAGOCYTOSIS" IN THE DESTRUCTION OF THE MICROORGANISMS IN THE LUNG

Phagocytosis of encapsulated Friedländer''s bacilli has been demonstrated in the lungs of rats in the absence of both circulating and local antibody. The mechanism of phagocytosis independent of antibody has been shown to be due to the same surface factors that operate in the phagocytosis of Type I pneumococcus under similar conditions. Direct observation of the phagocytic process reveals that leucocytes in the lung can phagocyte unopsonized Friedländer''s bacilli only by trapping them against the surfaces of alveolar walls or bronchi, or by pinning them against the surfaces of adjacent leucocytes. Evidence is presented that Friedländer''s bacilli thus phagocyted are rapidly killed in the cytoplasm of the phagocytic cells. Reasons are discussed for the failure of prolonged chemotherapy to cure lung abscesses that not infrequently complicate the pneumonia due to Friedländer''s bacillus.     

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.     

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.     

SOME OBSERVATIONS ON THE LYMPH AND BLOOD VESSELS OF THE RABBIT TRACHEA : WITH PARTICULAR REFERENCE TO THEIR R?LE IN THE PATHOGENESIS OF EXPERIMENTAL LOBAR PNEUMONIA.

1. Winternitz, Smith, and Robinson have offered as experimental evidence in support of the lymphatic path of infection in lobar pneumonia, a series of injection experiments of the rabbit''s tracheal submucosa. What these investigators supposed to be lymphatics are shown by us to be an unusual type of venous supply consisting of short, wide, and richly anastomosing vascular channels. 2. There is little homology between the structure and distribution of the lymph and blood vessels in the human and rabbit trachea. 3. Injections of pneumococci by the tracheal route to produce lobar pneumonia in the rabbit include an intravenous administration of these organisms when the mucosa is pierced or injured.     

STUDIES ON THE BACTERIOPHAGE OF D'HéRELLE : IX. EVIDENCE OF HYDROLYSIS OF BACTERIAL PROTEIN DURING LYSIS.

1. During the process of lysis by bacteriophage, there is an appreciable increase in the amount of free amino acid present in the culture. 2. The increase of free amino acid is due to hydrolysis of bacterial protein.     

QUANTITATIVE STUDIES ON THE PRECIPITIN REACTION : THE R?LE OF MULTIPLE REACTIVE GROUPS IN ANTIGEN-ANTIBODY UNION AS ILLUSTRATED BY AN INSTANCE OF CROSS-PRECIPITATION

1. Antisera to R-salt-azo-benzidine-azo-crystalline egg albumin give precipitates with crystalline egg albumin by virtue of their antidye content. 2. The quantitative course of the reactions with increasing amounts of antigen is very similar for the dye-antidye and egg albumin-anti-egg albumin systems, but differs markedly for the cross reaction between egg albumin and antidye. 3. A possible explanation for the occurrence of this one-sided crossreaction is given in terms of reactive groupings on the antigen and antibody. 4. A qualitative expression of the course of the cross-reaction is given in terms of the laws of classical chemistry.