398 BACTERIA IN CROUPOUS PNEUMONIA. 



served for a year or more. At a temperature of 40 C. development 

 ceases. 



Pathogenesis. In Friedlander's experiments the bacillus from 

 pure cultures, suspended in water, was injected through the thoracic 

 wall r into the right lung of dogs, rabbits, guinea-pigs, and mice. 

 Rabbits proved to be immune ; one dog out of five, six guinea-pigs 

 out of eleven, and all of the mice (thirty-two) succumbed to the 

 inoculation. At the autopsy the pleural cavities were found to con- 

 tain a sero-purulent fluid ; the lungs were intensely congested, con- 

 tained but little air, and in places showed limited areas of red infil- 

 tration ; the spleen was considerably enlarged ; the bacillus was 

 found in great numbers in the lungs, the fluid in the pleural cavi- 

 ties, and in the blood obtained from the general circulation or from 

 the various organs of the body. Similar appearances presented them- 

 selves in the case of the guinea-pigs which succumbed to the inocu- 

 lation. 



These results show that the bacillus under consideration is path- 

 ogenic for mice and for guinea-pigs, but they are by no means 

 sufficient to prove that it is capable of producing a genuine croupous 

 pneumonia in man, and it is still uncertain whether its occasional 

 presence in the exudate into the pulmonary alveoli in cases of this 

 disease has any etiological importance. 



MICROCOCCUS PNEUMONIA CROUPOS^Q. 



Synonyms. Micrococcus Pasteuri (Sternberg) ; Micrococcus of 

 sputum septicaemia (Frankel) ; Diplococcus pneumonise (Weichsel- 

 baum) ; Bacillus septicus sputigenus (Fliigge) ; Bacillus salivarius 

 septicus (Biondi) ; Lancet-shaped micrococcus (Talamon) ; Strepto- 

 coccus lanceolatus Pasteuri (Gameleia). 



Discovered by the present writer in the blood of rabbits inocu- 

 lated subcutaneously with his own saliva in September, 1880 ; by 

 Pasteur in the blood of rabbits inoculated with the saliva of a child 

 which died of hydrophobia in one of the hospitals of Paris in De- 

 cember, 1880 ; identified with the micrococcus in the rusty sputum of 

 pneumonia, by comparative inoculation and culture experiments, by 

 the writer in 1885 (paper published in the American Journal of the 

 Medical Sciences, July 1st, 1885). Proved to be the cause of croup- 

 ous pneumonia in man by the researches of Talamon, Salvioli, Stern- 

 berg, Frankel, Weichselbaum, Netter, Gameleia, and others. 



The Presence of Micrococcus Pasteuri in the Salivary Secre- 

 tions of Healthy Individuals. In September, 1880, while engaged 

 in investigations relating to the etiology of the malarial fevers, I in- 

 jected a little of my own saliva beneath the skin of two rabbits as a 

 control experiment. To my surprise the animals died, and I fomnd 



