Pathogenesis 405 



so that the pus is not chilled. In this way pure cultures which are 

 difficult to get from the soft sore itself, may be secured. 



Colonies. — The colonies appear upon the appropriate media in 

 about twenty-four hours, and attain their complete development in 

 about forty-eight hours. They are at first round bright globules, 

 and later become grayish and opaque. They measure i to 2 mm. 

 in diameter and never become confluent. They are difficult to pick 

 up with the platinum wire, tending to slide over the smooth surface 

 of the medium. 



Fig. 147. — Culture from ulceration on monkey resulting from inoculation of 

 culture from a case of chancroid of finger, first generation. Stained with carbol- 

 fuchsin and briefly decolorized by alcohol. Culture of twenty-four hours' 

 growth in rabbit's bouillon. X 1500 (Davis). (Photomicrograph by Mr. L. S. 

 Brown.) 



Vital Resistance. — The organisms seem to possess little vitality, 

 their life in artificial culture being limited to a few days. Fre- 

 quent transplantation enabled Davis to carry them on to the 

 eleventh cultural generation. 



Pathogenesis. — The organism is pathogenic for man and certain 

 monkeys (macacus), but not for the ordinary laboratory animals. 

 The organism can be found in large numbers in both the genital and 

 extragenital chancroidal lesions, and usually in small numbers in 

 the pus from chancroidal buboes. It has not been encountered 

 elsewhere. Lenglet* isolated the organism in pure culture, and by 

 inoculation with his cultures reproduced the lesions in man. 



* "Bull. Med." 1898, p. 1051; "Ann. de Dermatol. etdeSyph.," I90i,n,p. 209. 



