THE GENUS DIPLOCOCCUS 123 



strains appear which can scarcely be distinguished in 

 cultural relations, or in any other character than 

 pathogenesis, from the gonococcus. 



Schanz (1904) has recently summarized evidence from 

 many other sources as to the existence of atypical forms, 

 of the gonococcus or of forms allied to it, but differing 

 in growth on media, and in reaction to the Gram stain. 



The central type form may be defined as follows: 



2. D. gonorrhoeae (Neisser, Flugge). A coccus 

 occurring commonly in pairs of flattened coffee-bean shaped 

 cells. Decolorizes by Gram. Fails to develop, or develops 

 very feebly, on ordinary media. Not pathogenic for animals. 

 Occurs most abundantly in pus cells in gonorrheal infections. 

 Exhibits group serum reactions with D. W eichselbaumii. 



D. W eichselbaumii, a form closely related to D. gonor- 

 rhcece from the bacteriological standpoint, was first 

 clearly distinguished by Weichselbaum (1887), as the 

 commonest causative agent in epidemic cerebro-spinal 

 meningitis; and was named by him D. intracellulars 

 meningitidis. The trinomial specific name was replaced 

 by Trevisan (1889) with a proper binomial, D. Weich- 

 selbaumii. 



This coccus is found in the cerebro-spinal exudate, — 

 in largest numbers inside the leucocytes and other body 

 cells. Its characters have been very fully studied by 

 Bettencourt and Franca (1904). They found it occurring 

 usually in pairs of flattened cells, often in fours and 

 irregular masses, never in chains. It decolorized by 



