CULTIVATION OF GONOCOCCUS 



261 



The colonies vary somewhat in size, and tend to remain more or 

 less separate. Later, the margin tends to be undulated and the 



FIG. 74. Colonies of gonococcus on serum-agar ; (a) three days' growth ; 



(b) and (c) five days' growth. x9. 

 From photographs by Dr. W. B. M. Martin. 



centre more opaque ; a radial marking may be present (Fig. 74). 

 The first cultures die out somewhat quickly, but in sub-cultures, 

 kept at 37 C., the organism remains [alive^for a considerable 

 time, sometimes three 

 weeks. After about a 

 week more active foci of 

 growth may appear in 

 some of the colonies in 

 the form of heaped-up 

 opaque points, thus giving 

 an appearance suggestive 

 of contamination. In the 

 early stage of the disease 

 the organism is present in 

 the male urethra in practi- 

 cally pure condition, and if 

 the meatus of the urethra 

 be sterilised by washing 

 with weak solution of cor- 

 rosive sublimate and then 

 with absolute alcohol, and 

 the material for inocula- 

 tion be expressed from the 

 deeper part of the urethra, 



cultures may often be obtained which are pure from the first. 

 In culture the organisms have similar microscopic characters to 

 those described (Fig. 75), but show a remarkable tendency to 



FIG. 75. Gonococci, from a pure culture 

 on blood - agar of twenty-four hours' 

 growth. Some already are beginning to 

 show the swollen appearance common in 

 older cultures. 

 Stained with carbol-thionin-blue. x 1000. 



