510 Pneumonia 



and in the track of the wire innumerable little colonies 

 spring up and become confluent, so that a ' ' nail-growth ' ' 

 results. No liquefaction of the gelatin occurs. Gas bubbles 

 not infrequently appear in the wire track. The cultures 

 sometimes become brown in color when old. 



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 contains 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 16 C., and, according to Sternberg, has a thermal 

 death-point of 56 C. 



Metabolic Products. Friedlander'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. According to the best authorities the organism does not 

 form indol. There is, however, some difference of opinion 

 upon the subject. 



Perkins* divides the organisms of this group into three 

 chief types according to their reactions toward carbohy- 

 drates : 



I. Bacillus aerogenes type ferment all carbohydrates, 



with the formation of gas. 



II. Bacillus pneumoniae (Friedlander) type ferment all 

 carbohydrates except lactose, with formation of 

 gas. 



III. Bacillus lactis aerogenes type ferment all carbo- 

 hydrates except saccharose, with formation of 

 gas. 



Pathogenesis. Friedlander found considerable difficulty 

 in producing pathogenic changes by the injection of his 

 bacillus into the lower animals. Rabbits and guinea-pigs 

 were immune to its action, and the only important patho- 

 genic effects that Friedlander observed occurred in mice, 

 into whose lungs and pleura he injected the cultures, with 

 resulting inflammatory lesions. 



That Friedlander's bacillus may be the cause of true lobar 

 * ''Jour, of Infect. Dis.," 1904, i, No. 2, p. 241. 



