222 GONORRHOEA, SOFT SORE, SYPHILIS 



purposes of culture. The organism does not grow on gelatin, 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 

 temperatuft of 40 C. These are then successively inoculated with the 

 pus or other material in the same manner as gelatin tubes for ordinary 

 plates (vide p. 52). To each tube is added an equal part of ordinary 

 agar which has been thoroughly liquefied by heating and allowed to 

 cool also to 40 C. The mixture is then thoroughly shaken up and 

 quickly poured out on a plate or Petri's dish and allowed to solidify, 

 the plates being then incubated at a temperature of 37 C. The colonies 

 of the gonococcus are just visible in twenty-four hours, and are seen 

 both in the substance of the medium a"nd on the surface. The deep 

 colonies when examined with a lens are minute and slightly nodulated 

 spheres, sometimes showing little processes, whilst those on the surface 

 are thin discs of larger diameter with wavy margin and rather darker 

 centre. In this way the gonococcus may be separated from fluids which 

 are contaminated with a considerable number of other organisms. 



Relations to the Disease. The gonococcus is invariably 

 present in the urethral discharge in gonorrlwea, and also in 

 other parts of the genital tract when these are the seat of true 

 gonorrhoeal infection. Its presence in these different positions 

 has been demonstrated not only by microscopic examination 

 but also by culture. From the description of the conditions of 

 growth in culture, it will be seen that a life outside the body 

 in natural conditions is practically impossible a statement 

 which corresponds with the clinical fact that the disease is 

 always transmitted directly by contagion. Inoculations of pure 

 cultures on the urethra ' of lower animals, and even of apes, is 

 followed by no effect, but a similar statement can be made with 

 regard to inoculations of gonorrhoeal pus itself. In fact, 

 hitherto it has been found impossible to reproduce the disease by 

 any means in the lower animals. On a considerable number of 

 occasions inoculations of pure cultures have been made on the 

 human urethra, both in the male and female, and the disease, 

 with all its characteristic symptoms, has resulted. (Such 

 experiments have been performed independently by Bumm, 

 Steinschneider, Wertheim, and others.) The causal relationship 

 of the organism to the disease has therefore been completely 



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



gelatin, i.e. ordinary peptone gelatin 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. 



