STOCK CULTURES OF THE MENINGOCOCCUS 71 



negligible, those of individual cocci seeming to be determined 

 more by the age of the culture, than by the culture medium. De- 

 generation forms occur with all strains in quite young cultures. 

 The potato-blood-agar furthermore is of value for differentia- 

 ting between the meningococcus and the gonococcus; on this 

 medium the gonococcus grows only when the medium has a high 

 blood and diminished salt content — the growth is always very 

 scanty and the characteristic differences are immediately apparent. 



