Pathogenesis 



303 



Agar-agar. Upon the surface of 

 agar-agar at ordinary temperatures 

 a luxuriant white or brownish -yellow, 

 smeary, viscid, circumscribed growth 

 occurs. 



Blood-serum. The blood-serum 

 growth is similar to that upon agar. 



Potato. Upon potato the growth 

 is luxuriant, quickly covering the 

 entire surface with a thick yellowish- 

 white layer, which sometimes con- 

 tains bubbles of gas. 



Milk is not coagulated as a rule. 

 Litmus milk is reddened. 



Vital Resistance. The bacillus 

 grows at a temperature as low as 

 1 6 C., and, according to Sternberg, 

 has a thermal death -point of 56 C. 



Metabolic Products. Friedlan- 

 der's bacillus ferments nearly all the 

 sugars with the evolution of much 

 gas. It generates alcohol, acetic 

 and other acids, and both CO 2 and 

 H. It also produces indol. 



Pathogenesis. Friedlander found 

 considerable difficulty in producing 

 pathogenic changes by the injec- 

 tion of his bacillus into the lower 

 animals. Rabbits and guinea-pigs 

 were immune to its action, and the 

 only important pathogenic effects 

 that Friedlander observed occurred 

 in mice, into whose lungs and pleura 

 he injected the cultures, with result- 

 ing inflammatory lesions. 



Curry * found Friedlander's bacil- 

 lus in association with the pneumo- 

 coccus in acute lobar pneumonia; in 

 association with the diphtheria bacil- 

 lus in otitis media associated with 

 croupous pneumonia; and in the 



* "Jour. Boston Soc. of Med. Sci.," 

 March, 1898, vol. n, No. 8, p. 137. 



Fig. 88. Friedlan- 

 der's pneumobacillus ; 

 gelatin stab culture, 

 showing the typicai 

 nail-head appearance 

 and the formation or 

 gas bubbles, not always 

 present (Curtis). 



