THE DUCREY BACILLUS OF SOFT CHANCRE 373 



tube, to which the pus from the ulcerated bubo is then added in proper 

 proportion, and the whole placed in the incubator at 35 C. The pus 

 may be obtained by puncture and aspiration from the unbroken ulcer, 

 or if the ulcer is already open it is first painted with tincture of iodine 

 and covered with collodion or sterile gauze. After twenty-four to 

 forty-eight hours, some pus having collected under the bandage, inocu- 

 lations are made from it. The bacillus grows well also in uncoagulated 

 rabbit-blood s rum or in condensation water of blood agar. In twenty- 

 four to forty-eight hours, on the surface of the media, well-developed, 

 shining, grayish colonies, about 1 mm. in diameter, may be observed. 

 The colonies remain separate, but only become numerous after further 

 transplantation. The best results are obtained when the pus is taken 

 close to the walls of the abscess. 



Glass smears show isolated bacilli or short parallel chains with dis- 

 tinct polar staining. 



After the eleventh generation of the culture, and from all old cul- 

 tures, on inoculation the characteristic soft chancre is produced in 

 man. According to some observers animals cannot be infected; others 

 claim to have obtained positive results with monkeys and cats. 



The organisms are especially characteristic in the water of condensa- 

 tion from blood agar, the bacilli being thinner and shorter, with rounded 

 ends; sometimes long, wavy chains are found. In rabbit-blood serum 

 at 37 C. a slight clouding of the medium is produced and small flakes 

 are formed, consisting of short bacilli or moderately long, curved chains, 

 showing polar staining. 



The bacillus lives several weeks on blood agar at 37 C., but it 

 soon dies in cultures on coagulated serum. All other ordinary culture 

 media so far tried have given negative results, and even with the media 

 described development is difficult and often fails entirely. 



The chancre bacillus possesses but little resistance to deleterious out- 

 side influences. Hence, the various antiseptic bandages, etc., used in 

 treatment of the affection soon bring about recovery by preventing 

 the spread of inoculation chancre. 



