GONOCOCCUS 173 



It is seldom a strain of the gonococcus will grow on ordinary 

 nutrient agar; as a rule it requires the addition of blood serum 

 or other body fluid. Colonies appear within twenty-four to 

 forty-eight hours as delicate, finely granular disks with scalloped 

 margins ; in color they are grayish white with a tinge of yellow. 

 When freshly isolated the organisms die in from two to three 

 days unless transplanted ; older cultures may live three weeks and 

 if kept in the ice box even longer. 



Comparison with Meningococcus. Morphologically and cul- 

 turally the two organisms resemble each other very closely. The 

 following points are of importance in differentiating them. The 

 meningococcus grows on culture media more readily than the 

 gonococcus. After the first subculture it will frequently grow on 

 nutrient agar, whereas the gonococcus will rarely grow on ordinary 

 agar. The colonies of the latter are less opaque and have a more 

 irregular margin than those of the meningococcus. The meningo- 

 coccus grows well in broth with a neutral reaction, producing a 

 general turbidity; whereas the gonococcus does not grow, and 

 even if serum is added growth is very scanty and falls to the 

 bottom as a deposit, leaving the medium clear. Of the sugars 

 usually employed the gonococcus ferments glucose only, the 

 meningococcus ferments maltose also. As a rule the part of the 

 body from which the organisms are obtained gives sufficient 

 information. 



Resistance. The gonococcus is very feebly resistant to 

 harmful influences. It is quickly destroyed by drying when in 

 thin layers of pus ; in comparatively thick layers smeared on linen 

 it has been found alive after several days. The organism has 

 never been found apart from the human body or material ob- 

 tained from it. 



Pathogenesis. All attempts to reproduce the disease in lower 

 animals has so far failed. Intraperitoneal injections of living 

 cultures into white mice produce peritonitis, but the organisms 

 appear to be unable to multiply and soon disappear. Injected 

 into the joints of rabbits and dogs, they cause an acute inflamma- 

 tion which soon subsides and the gonococci can no longer be 



