BACTERIA IN PNEUMONIA 159 



Pathogenesis. Rabbits and guinea-pigs, if subcutaneously 

 injected, die in the course of a couple of days with septicemia 

 (o.i c.c. of a fresh bouillon culture suffices). 



Autopsy shows greatly enlarged spleen and myriads of 

 micrococci in the blood and viscera, the lungs not especially 

 affected. If injected into the trachea, a pneumonia occurs. 

 In man they are found in 90 per cent, of croupous pneumonia, 

 and usually only during the existence of the rusty sputum, 

 i. ., the first stage. Found in the tissue of the inflamed 

 lung, and in the blood in nearly all cases of lobar pneumonia. 



The pneumococcus has also been found in pleuritis, peri- 

 tonitis, pericarditis, meningitis, and endocarditis. It stands 

 in some intimate relation to all infectious inflammations of 

 the body. Their presence in healthy mouth secretion does 

 not speak against this, it requiring some slight injury or low- 

 ered resistance to allow this ever-present germ to produce a 

 pneumonia from an infectious disease like measles or in- 

 fluenza. 



Toxins and antitoxins have not been separated or demon- 

 strated. The poisons are probably endotoxins, and closely 

 connected with the cell-body. Agglutination properties of 

 pneumonia blood serum, if any, are very weak i : 50. 



Immunity and Serum Therapy. One attack produces no 

 immunity; and no immune serum has been found of any value. 

 By growing in an acid medium, the organism has been ren- 

 dered less virulent. 



Bacillus Pneumonias (Friedlander, 1882). Synonym. 

 Capsule Bacillus of Pfeiffer. Once supposed to be a cause of 

 pneumonia. It grows readily on ordinary media; is Gram 

 negative; in form and capsule formation it sometimes re- 

 sembles the pneumococcus (Fig. 70). 



Bacillus of Rhino scleroma (Frisch, 1882). It was found 

 in the tissue of a rhinoscleroma, but resembles the Fried- 

 lander bacillus in nearly every respect, and as the disease 

 rhinoscleroma is not reproduced by the inoculation of the 

 bacillus in animals, it can be considered identical. The 



