MICROCOCCUS GONORRHCE^E 245 



the pus-cells (Plate III. &). The individual cocci vary 

 somewhat in size, the average being about 0*7 //, in the 

 long and 0-5 JUL in the short diameter. It stains readily 

 with the ordinary anilin dyes, Loffler's blue being perhaps 

 the best, but is decolorised by Gram's method an im- 

 portant practical distinction from many other cocci. 



Cultural characters. The gonococcus is difficult to 

 cultivate, and usually soon dies out under cultivation 

 within a week, unless transferred to fresh soil but it 

 does not seem to lose its virulence. Growth takes place 

 between 25 and 38 C., but the optimum temperature 

 is between 35 and 37 C. It is aerobic, and possibly 

 facultatively anaerobic, and will develop on a feebly 

 alkaline or acid soil. The ordinary agar and gelatin 

 media are useless for the cultivation of the gonococcus ; 

 it will grow only on a medium containing " native " 

 protein. Blood- serum agar gives fair results, but the 

 ordinary Loffler's blood-serum is of no use. The best 

 medium is agar smeared with blood. Ordinary sloping 

 agar tubes or small agar plates may be employed. Blood 

 obtained by pricking the finger, with antiseptic precautions, 

 is taken up in a sterile capillary tube and deposited on 

 the agar. A trace of gonorrhoeal pus, collected with 

 aseptic precautions, is taken up on a small sterile camel's- 

 hair brush, and is rubbed up with the drop of blood and 

 smeared over the surface of the agar. The cultures are 

 incubated at 37 C., and in twenty-four hours the colonies 

 of the gonococci appear as transparent greyish specks, 

 which increase in size up to the end of three days. At this 

 stage the colony measures 1 to 2 mm. in diameter, is 

 raised, brownish, and finely granular in appearance, and 

 roundish with a crinkled margin. The cocci from cultures 

 resemble those in the pus, but tetrads are more frequently 

 met with. Egg-broth also gives good results. The fer- 

 mentation reactions and comparison with other Gram- 



