CULTIVATION OF GONOCOCCUS, 



173 



from the first. By successive sub-cultures at short intervals, 

 growth may be maintained indefinitely, and the organism 

 gradually flourishes more luxuriantly. In culture the 

 organisms have similar microscopic characters to those 

 described (Fig. 49), but show a remarkable tendency 

 to undergo degenera- 

 tion, becoming swol- 

 len and of various 

 sizes, and staining 

 very irregularly. 

 Degeneration forms 

 are seen even on the 

 second day, and in a 

 culture four or five . 



days old compara- . 



tively few normal 

 cocci may be found. 

 The less suitable the 

 medium the more 

 rapidly does degenera- FlG 49 ._ Go nococci, from a pure culture 



tion take place. on blood agar of twenty-four hours' growth. 



On ordinary agar Some already are beginning to show the 

 , swollen appearance common in older cultures. 



and on glycerine agar Stained with carbo i_ thionin . blue . x I000 . 

 growth does not take 



place, or is so slight that these media are quite unsuitable 

 for purposes of culture. The organism does not grow on 

 gelatine, 1 potato, etc. 



Plate- Cultures. The following ingenious method of 

 plate-culture was introduced by Wertheim for the culture 

 of the gonococcus. The medium of culture is a mixture 

 of human blood serum and of ordinary agar (2 per cent) 

 in equal parts. The serum, in a fluid and sterile condition, 

 is put in suitable quantities into two or three test tubes 

 and brought to a temperature of 40 C. These are then 



1 Turro has announced that he has cultivated the gonococcus on acid 

 gelatine, i.e., ordinary peptone-gelatine which has not been neutralised. 

 We have failed to obtain any growth of the gonococcus on this medium, 

 even when inoculation was made from a vigorous growth on blood agar. 



