242 EPIDEMIC CEREBRO-SPINAL MENINGITIS 



and by carbol-fuchsin, etc. (pp. 105, 108), in the latter case 

 it is usually best not to decolorise the groundwork of the 

 preparation. 



(2) By cultures, (a) FraenkeVs pneumococcus. With similar 

 material make successive strokes on agar, blood agar, or blood 

 serum. The most certain method, however, is to inject some 

 of the material containing the suspected cocci into a rabbit. If 

 the pneumococcus be present the animal will die, usually within 

 forty -eight hours, with numerous capsulated pneumococei in its 

 heart blood. With the latter inoculate tubes of the above media 

 and observe the growth. In some cases of severe pneumococcic 

 infection the organism may be cultivated from the blood obtained 

 by venesection (p. 72). (b) Friedlander 's pneumohacillus can 

 be readily isolated either by ordinary gelatin plates or by 

 successive strokes on agar media. 



EPIDEMIC CEKEBRO-SPINAL MENINGITIS. 



As the result of observations on this disease in different parts 

 of the world, it has been now established that the causal agent 



is the diplococcus intra- 

 cellularis meningitidis, 

 first described by Weich- 

 selbaum, and now often 

 known as the meningo- 

 coccus. This organism is 

 a small coccus measuring 

 about 1 /ji in diameter 

 and usually occurs in 

 pairs, the adjacent sides 

 being somewhat flattened 

 against each other. In 

 most cases the cocci are 

 chiefly contained within 

 polymorphonuclear leuco- 

 cytes in the exudation 



FIG. 70. Film preparation of exudation from (Fig. 70) ; ill some cases, 



a case of meningitis showing -the diplococci however) the ma j or i ty 



within leucocytes. See also Plate I., Fig. 3. > . J J 



Stained with carbol-thionin-blue. x 1000. may be lying tree. It 



stains readily with basic 



aniline dyes, but loses the stain in Gram's method. Both 

 in appearance and in its staining reactions it is similar to 

 the gonococcus (vide infra}. The organism can readily be 

 cultivated outside the body, but the conditions of growth 



