290 Pneumonia 



The capsules are more distinct when the examination is 

 made in water. 



Hiss* recommends the following as an excellent method 

 of staining the capsules of the pneumococcus : The organism 

 is first cultivated upon ascites-serum-agar to which i per 

 cent, of glucose is added. The drop containing the bacteria 

 to be stained is spread upon a cover-glass mixed with a 

 drop of serum or a drop of the fluid culture medium, and 

 dried and fixed. A half -saturated aqueous solution of gen- 

 tian violet is applied for a few seconds and then washed 



Fig. 84. Capsulated pneumooocci in blood from the heart of a rabbit ; 

 carbol-fuchsin, partly decolorized. X 1000. 



off in a 25 per cent, solution of carbonate of magnesium. 

 The preparation is then mounted in a drop of the latter 

 solution and examined. 



If it is desired to stain the capsules and preserve the 

 specimens permanently in balsam, Hiss employs a 5 or 10 

 per cent, solution of fuchsin or gentian violet (5 c.c. saturated 



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

 p. 302, March 24, 1902 



