PNEUMONIA. 353 



prefers to call it, the Bacillus pneumoniae has ceased to 

 be regarded as specific, and is now looked upon as an 

 accidental organism whose presence in the lung is, in 

 most cases, unimportant. 



As the two organisms are similar in more respects than 

 their names, Friedlander's bacillus requires at least a 

 brief description. 



It is distinctly a bacillus, but sometimes, when occur- 

 ring in pairs, has a close resemblance to the pneumo- 

 coccus of Frankel and Weichselbaum. Very frequently 

 it forms chains of four or more elements. It is also com- 

 monly surrounded by a transparent capsule. It is non- 

 motile, has no spores and no flagella. It stains well 

 with the ordinary anilin dyes, but does not retain the 

 color when stained by Gram's method. 



Frankel points out that Friedlander's error in suppos- 

 ing this bacillus to be the chief parasite in pneumonia 

 depended upon the fact that his studies were made by 

 the plate method. If some of the pneumonic exudate be 

 mixed with gelatin and poured upon plates, the bacilli 

 grow into colonies at the end of twenty-four hours, and 

 appear as small white spheres which spread upon the 

 gelatin to form white masses of a considerable size. 

 Under the microscope these colonies are rather irregular 

 in outline and somewhat granular. 



The bacillus grows at as low a temperature as 16 C., 

 and, according to Sternberg, has a thermal death-point 

 of 56 C. 



When a colony is transferred to a gelatin puncture-cul- 

 ture, quite a massive growth occurs. Upon the surface a 

 somewhat elevated, rounded white mass is formed, and 

 in the track of the wire innumerable little colonies 

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

 results. No liquefaction occurs. When old the cultures 

 sometimes become brown in color. 



Upon the surface of agar-agar at ordinary temperatures 

 quite a luxuriant white or brownish-yellow, smeary, cir- 



23 



