466 



Pneumonia 



dye in 95 cc. of distilled water). The stain is applied to the fixed 

 specimen and heated until it begins to steam, when the stain is 

 washed off in a 20 per cent, solution of crystals of sulphate of copper. 

 The preparation is then dried and mounted in balsam. 



HSss found this stain a useful aid in differentiating the pneumo- 

 coccus from the streptococcus, with which it is easily confounded if 

 the capsules are not distinct. 



Isolation. — When desired for purposes of study, the pneumococcus 

 may be obtained by inoculating beneath the skin or into the peri- 

 toneal cavity pneumonic sputum of white mice and recovering the 

 organisms from the heart's blood, or peritoneal fluid. Or it may be 

 obtained from the rusty sputum of pneumonia by the method em- 



Fig. 168. — Capsulated pneumococci in blood from the heart of a rabbit; carbol- 

 fuchsin, partly decolorized. X 1000. 



ployed by Kitasato for securing tubercle bacilli from sputum: A 

 mouthful of fresh sputum is washed in several changes of sterile 

 water to free it from the bacteria of the mouth and pharynx, care- 

 fully separated, and a minute portion from the center transferred 

 to an appropriate culture-medium. 



Buerger,* in conducting a research upon pneumococcus and allied 

 organisms with reference to their occurrence in the human mouth, 

 used a 2 per cent, glucose-agar of a neutral, or, at most, 0.5 per cent, 

 phenolphthalein acid titer. 



"The medium was usually made from meat infusion and contained i.i to 2 

 per cent, peptone and 2.4 per cent. agar. Stock plates of these media (serum- 

 agar and 2 per cent, glucose-serum-agar) were poured. The agar or glucose- 

 agar was melted in large tubes and allowed to cool down to a temperature below 

 the coagulation point of the serum. One-third volume of rich albuminous 

 ascitic fluid was added, and the resulting media poured into Petri plates. These 

 were tested by incubation and stored in the ice-chest ready for use. . . . 



"Thet^lan finally adopted [for inoculating the plates] was as follows :?A 

 swab taken from the mouth was thoroughly shaken in a tube of neutral bouillon. 

 From this primary tube, dilutions in bouillon with four, six, and eight loops 

 *"Jour. Exp. Med.," Aug. 25, 1905, vn, No. 5. 



