640 THE GONOCOCCUS 



filter paper. Distribute in small Erlenmeyer flasks and sterilize by heating 

 at 100 C. on three separate occasions during the next 24 hours. Then add 

 the liquid which is colourless or pale yellow, transparent, and alkaline to 

 litmus to ordinary nutrient agar in the proportion of 1-3 of agar. A broth 

 may be prepared with albumin in a similar manner. 



Milk-agar. Milk added to glycerin-agar constitutes a very good medium 

 for the growth of the gonococcus (Bruschettini and Ansaldo). 



Steinschneider's agar is prepared by mixing one part of human urine 

 collected aseptically with two parts of sterile agar (the technique is the same 

 as for Wertheim's agar). 



Bumm's serum. Bumm uses solidified human serum. The blood is 

 collected with aseptic precautions during confinement. 



Immediately after cutting the umbilical cord, the placenta being still in the 

 uterus, wash the central end in corrosive sublimate solution, and allow the blood 

 to flow into a sterile flask. In this way as much as 100 c.c. of blood can be collected 

 and from the blood a perfectly clear serum can be drawn off 18-24 hours later which 

 is then solidified in the ordinary way. 



It is easier to use blood collected from a vein of the forearm (p. 193). The 

 characteristics of the growth on human serum are the same as on Wertheim's 

 agar. 



De Christmas uses coagulated rabbit serum instead of human serum and 

 cultivates the organism in tubes of small diameter. 



Potato. No growth takes place on potato. On glycerin-potato Bruschettini 

 and Ansaldo obtained a good growth by sowing from a white-of-egg-broth 

 culture. 



SECTION III. BIOLOGICAL PROPERTIES. 

 1. Viability. Virulence. 



Gonorrhceal pus is sterilized in a few minutes by heating at a temperature 

 of 55 C. Similarly if kept at a temperature of C. in an ice chest for a 

 few hours cultures cannot be obtained on sowing the material. Desiccation 

 and exposure to the air will rapidly sterilize gonococci in pus. The weakest 

 antiseptics are sufficient to kill the organism. 



The gonococcus has very little viability in cultures. If kept in the incubator 

 the cultures may live 2 or 3 weeks but if kept at the ordinary temperature only 

 a few hours. Successive sub-cultures soon become unfertile ; as a rule sub- 

 cultures fail to grow after the fourth or fifth generation, but on media con- 

 taining albumin, Leipschutz succeeded in cultivating the organism for thirty- 

 five generations. 



Young cultures on suitable media are virulent but the virulence is soon 

 lost. The lesions produced in animals by cultures are chiefly due to the 

 toxin inoculated at the same time. The virulence of any strain of the organism 

 may be increased by passage through rabbits (p. 635). 



2. Toxin. 



The toxin of the gonococcus was studied by De Christmas, and his results 

 were confirmed by Wassermann and Nicolaysen. These observers found 

 that the toxin is almost exclusively intra-cellular whence it diffuses only 

 very slowly into the surrounding media. Morax and Elmassian obtained 

 an active toxin by macerating gonococci in a 1 per cent, solution of potash 

 for a week or 10 days. 



Preparation of the toxin. For the cultivation of the organism De Christmas 

 at first used a mixture of one-third ascitic fluid and two-thirds peptone 



