232 GONORRHOEA, SOFT SORE, SYPHILIS. 



but more deeply situated than other organisms, and may be 

 present in a state of purity amongst the leucocytic infiltration. 

 In this position it is usually arranged in chains which may be 

 of considerable length, and which are often seen lying in parallel 

 rows between the cells. The bacilli chiefly occur in the free con- 

 dition, but occasionally a few may be contained within leucocytes. 



This bacillus takes up the basic aniline stains fairly readily, 

 but loses the colour very rapidly when a decolorising agent is 

 applied. Accordingly, in film preparations when dehydration is 

 not required, it can be readily stained by most of the ordinary 

 combinations, though LofBer's or Kiihne's methylene-blue solu- 

 tions are preferable, as they do not overstain. In sections, how- 

 ever, great care must be taken in the process of dehydration, 

 and the aniline-oil method (vide p. 96) should be used for this 

 purpose, as alcohol decolorises the organism very readily. A 

 little of the methylene-blue or other stain may be with advantage 

 added to the aniline oil used for dehydrating. 



This organism has not yet been successfully cultivated out- 

 side the body, though practically every medium has been tried 

 for this purpose. Ducrey, however, succeeded in separating it 

 from other organisms by the following method. He produced 

 a series of pustules by successive inoculations in the human 

 subject on the skin, which had been previously sterilised, the 

 pustules being afterwards protected from contamination by 

 watch-glasses fixed in position. He found that in this method 

 the other organisms gradually died off, while the characteristic 

 bacilli persisted, and at about the fifth or sixth inoculation might 

 be present alone. Further, the pus containing the bacilli in a 

 pure condition still produced the typical lesion on inoculation. 

 Even when the organisms were thus separated he failed to 

 obtain any growth on the numerous media which he employed. 



The evidence that this organism is the causal agent in the 

 affection accordingly rests on the facts well established that the 

 organism is apparently always present in the discharge from 

 the sore, and in its tissues ; that it has been observed hitherto in 

 no other form of ulceration ; and that it is sharply marked off 

 from saprophytic organisms by the fact that it has not been 

 obtained in cultures outside the body. 



Regarding the presence of this organism in the buboes asso- 

 ciated with soft sore, there is some uncertainty. , A considerable 



