124 RELATIONSHIPS OF THE COCCACE/E 



Gram. Scum and turbidity appeared in broth (contain- 

 ing cerebro-spinal fluid), and on ascites-agar the organ- 

 ism appeared in small yellowish brown colonies with crystal- 

 line deposits at their margin. The behavior of the coccus 

 in other media, and under the action of various unfavor- 

 able agents, is fully described in the original paper. In 

 general, the meningococcus differs from the gonococcus, 

 culturally, by the fact that it grows more readily on ordi- 

 nary media. In this respect D. Weichselbaumii is in- 

 termediate between D. pneumonia and D. gonorrhoea. 



The meningococcus exhibits a slight degree of virulence 

 for the ordinary laboratory animals, being more patho- 

 genic than D. gonorrhoea but much less pathogenic than 

 the pneumococcus. 



Dr. Wollstein (1907) and other observers have recently 

 shown that D. gonorrhoea and D. Weichselbaumii are 

 closely related in their reactions to immune sera. Agglu- 

 tinins, aggressins, protective power, and amboceptors 

 developed in the bodies of immunized animals are common 

 to the two forms and distinct from the products charac- 

 teristic of Str. pyogenes and D. catarrhalis. The better 

 viability of D. Weichselbaumii on culture media and its 

 somewhat higher virulence are the only distinguishing 

 marks of the two species, aside from their differing patho- 

 genic effects in man. 



As in the other types of this genus, a long contest has 

 been waged over the problem of variability among the 

 meningococci. Jaeger (1902) and others claimed to 



