PNEUMONIA. 



281 



grown ordinarily in culture-media, and especially upon 

 solid media, the capsules are absent. 



The organism is without motility, has 110 spores, and 

 does not seem to be able to resist any unfavorable con- 

 ditions when grown artificially. It stains well with the 

 ordinary solutions of the anilin dyes, and gives most 

 beautiful pictures in blood and tissues when stained by 

 Gram's method. The capsule does not stain. 



To demonstrate the capsule, the glacial acetic acid 



Fig. 61. — Capsulated pneumococci in blood from the heart of a rabbit; carbol- 

 fuchsin, partly decolorized ; x iooo. 



method of Welch ' may be used. The cover-glass is 

 spread with a thin film of the material to be examined, 

 which is dried and fixed as usual. Glacial acetic acid is 

 dropped upon it for an instant, poured (not washed) off, 

 and at once followed by anilin-water gentian-violet, in 

 which the staining continues several minutes, the stain 

 being poured off and replaced several times until the acid 



1 Bulletin of the Johns Hopkins Hospital, Dec, 1892, p. 128. 



