494 Pneumonia 



is without motility, has no flagella, forms no spores, and 

 seems unable long to resist unfavorable conditions when 

 grown artificially. 



Staining. 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 and Weigert's methods. 



To demonstrate the capsules, the glacial acetic acid 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 



Fig. 161. Capsulated pneumococci in blood from the heart of a rabbit; 

 carbol-fuchsin, partly decolorized. X 1000. 



for an instant, poured (not washed) off, and at once followed 

 by anilin-water gentian violet, in which the staining con- 

 tinues several minutes, the stain being poured off and 

 replaced several times until the acid has all been removed. 



Finally, the preparation is washed in water containing i or 

 2 per cent, of sodium chlorid, and may be examined at once 

 in the salt solution, or mounted in balsam after drying. 

 The capsules are more distinct when the examination is 

 made in water. 



Hissf recommends the following as an excellent method 



* "Bull, of the Johns Hopkins Hospital," Dec., 1892, p. 128. 



t Abstract, "Centralbl. f. Bakt. u. Parasitenk.," Bd. xxxi, No. 10, p. 

 302, March 24, 1902. More complete details appear in a later paper in 

 the "Journal of Experimental Medicine," vi, p. 338. 



