258 GONOKRHCEA AND SOFT SORE 



undergo degeneration, becoming swollen and of various sizes, 

 and staining very irregularly. Degenerated forms are seen even 

 on the second day, whilst in a culture four or five days old com- 

 paratively few normal cocci may be found. The less suitable 

 the medium the more rapidly does degeneration take place. 

 When mixed with other organisms the gonococcus may be 

 separated by serum-agar plates (p. 43). 



On ordinary agar and on glycerin-agar some growth may 

 take place when the reaction is just alkaline to litmus, but these 

 media are quite unsuitable for ordinary purposes. The organism 

 does not grow on gelatin, potato, etc. 



Comparison with Meningococcus. — The morphological and cultural 

 characters of the gonococcus and meningococcus are in many respects 

 closely similar ; the following points are of importance in distinguishing 

 them. The conditions of growth of the gonococcus are more restricted 

 than those of the meningococcus. The gonococcus usually does not grow 

 on the ordinary agar media, whereas the meningococcus grows fairly 

 well, at least after the first sub-culture. The colonies of the latter are 

 rather more opaque and have more regular margins than those of the 

 gonococcus. The meningococcus grows well in neutral bouillon, produc- 

 ing a general turbidity, whereas the gonococcus does not grow ; even in 

 serum bouillon the latter organism flourishes feebly, and the scanty 

 growth falls to the bottom leaving the medium clear, whilst the 

 meningococcus produces abundant growth with general turbidity. The 

 fermentative effects have also been studied, and the chief results 

 obtained are that glucose is the only sugar usually employed which is 

 fermented by the gonococcus, whereas the meningococcus ferments 

 maltose also. (For fermentative tests in the case of the gonococcus, 

 solid media, as introduced by v. Lingelsheim, should be used, the serum 

 medium of Martin, with litmus or neutral-red, and the particular sugar 

 added, being specially suitable.) 



Specific serum reactions — agglutination, opsonic action, 

 bactericidal action, and fixation of complement — have been 

 studied by Torrey, Elser and Huntoon, and Martin, in the case 

 of the two organisms. The general results obtained are that 

 each organism represents a somewhat heterogeneous group 

 showing considerable variations as regards the tests mentioned 

 (vide also p. 249). An anti-gonococcus serum produced by 

 injecting one strain of gonococcus has the maximum effect on 

 that strain, whilst its action on other strains may be much 

 feebler. An anti-gonococcus serum may have some effect, 

 usually slight, on a meningococcus and vice versa ; this indicates 

 that there are some receptors common to the two organisms. 

 Arkwright finds that the complement-fixation test does not 

 supply a satisfactory distinction between gonococci and 

 meningococci. 



