232 THE ACUTE PNEUMONIAS 



agglutinate the streptococcus mucosus more readily than other 



streptococci. All the facts seem to point to this organism being 



closely allied to the true pneumococcus. 



The Cultivation of Friedlander's Pneumobacillus. This 



organism, when present in sputum or in a pneumonic lung, can 

 ... i~< be readily separated by making ordinary 



gelatin plate cultures, or a series of suc- 

 cessive strokes on agar tubes. The surface 

 colonies always appear as white discs 

 which become raised from the surface so 

 as to resemble little knobs of ivory. 

 From these, pure cultures can be readily 

 obtained. The appearance of a stab cul- 

 ture in gelatin is very characteristic. 

 At the site of the puncture, there is on 

 the surface a white growth heaped up, 

 it may be fully one-eighth of an inch, 

 _,;.;,% above the level of the gelatin; along the 



needle track there is a white granular 

 appearance, so that the whole resembles 

 a white round-headed nail driven into 

 the gelatin (Fig. 67). Hence the name 

 " nail-like " which has been applied. 

 Occasionally bubbles of gas develop along 

 the line of growth. There is no lique- 

 faction of the medium. On sloped agar 

 it forms a very white growth with a 

 shiny lustre, which, when touched with 

 a platinum needle, is found to be of a 

 viscous consistence. In cultures much 

 ^>i i M*^ longer rods are formed than in the 



FIG. 67.-Stab culture of tisSUGS f the bod y ( Fi S' 68 )' On tlle 

 Friedlander's pneumo- surface of potatoes it forms an abundant 

 bacillus in peptone moist white layer. It is non-motile. 

 nalSe "appearance Friedlander's bacillus has active ferment- 

 ten days' growth.' ing powers on sugars, though varieties 

 Natural size. isolated by different observers vary in 



the degree in which such powers are 

 possessed. It always seems capable of acting on dextrose, 

 lactose, maltose, dextrin, and mannite, and sometimes also on 

 glycerin. The substances produced by the fermentation vary 

 with the sugar fermented, but include ethylic alcohol, acetic 

 acid, laevolactic acid, succinic acid, along with hydrogen and 

 carbonic acid gas. The amount of acid produced from lactose 



