212 INFLAMMATORY AND SUPPURATIVE CONDITIONS. 



delicate organism. There has been described by Eyre and 

 Washbourn a non-pathogenic type of the pneumococcus which 

 may be found in the healthy mouth, and which may also be 

 produced during the saprophytic growth of the 

 virulent form. From the latter it differs generally 

 in its more Vigorous growth, in producing a uniform 

 cloud in bouillon, in slowly liquefying gelatin, and 

 in growing on potato. 



The Cultivation of Friedlander's Pneumoba- 

 cillus. This organism, when present in sputum 

 or in a pneumonic lung, can be readily separated 

 by making ordinary gelatin plate-cultures, or a 

 series of successive strokes on agar tubes. The 

 surface colonies always appear as white discs, 

 which become raised from the surface so as to 

 appear like little knobs of ivory. From these, 

 pure cultures can be readily obtained. The ap- 

 pearance of a stab-culture in gelatin growth 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 



3IS 



Crt< 



/>3i 



..j 



*fr r . 



'<u-*-' 



^ ^ 



/***:?; ** v % *V*'V 



*KJT V fc *' *~ ^ \ Vi*' 



'* "^ \ JP \- '* * % <- 

 i *^& A* v *"' 



FIG. 82. Stab- 

 culture of Fried- the level of the 

 lander's pneumo- ge l at in ; along 

 bacillus in peptone 



gelatin, showing the the needle track 



nail-like appear- 4-u prp : Q w V>if P 



Llld.^ lo CL W111LC 



ance ; ten days 



growth. Natural granular ap- 

 pearance,sothat 

 the whole resembles a white 

 round-headed nail driven into 

 the gelatin (Fig. 82). Hence 

 the name "nail-like" which has ; /~V v'^ * ^ * -\ * 

 been applied. Occasionally * t ^ .^"^ V^ * 



bubbles of gas develop along - * *3P ^ 



the line Of growth. There is no Fl - 83. Friedlander's pneumobacillus.i 



- . .. _ from a young culture on agar ; showing some 



liquefaction Of the medium. On rod-shaped forms. Stained with thionin- 



sloped agar it forms a very blue - x I00 - 



white growth with a shiny lustre, which, when touched with a 



1 The apparent size of this organism, on account of the nature of its sheath, varies 

 much according to the stain used. If stained with a strong Stain, e.g. carbol-fuchsin, 

 its thickness appears nearly twice as great as is shown in the figure. 



