ZUR NEDDEN'S BACILLUS 547 



become liquefied. Upon serum agar delicate grayish drop-like colonies 

 are formed which are not unlike those of the gonococcus. 



In ascitic bouillon general clouding occurs within twenty-four hours. 



Pathogenicity. — Attempts to produce lesions in the lower animals 

 with this bacillus have been universally unsuccessful. Subacute con- 

 junctivitis, however, has been produced in human beings by inocula- 

 tions with pure cultures. 



ZUR NEDDEN'S BACILLUS 



In ulcerative conditions of the cornea, Zur Nedden has frequently 

 found a bacillus to which he attributes etiological importance. 



The bacillus which he has described is small, usually less than 

 one micron in length, often slightly curved, and generally found singly. 

 It may be found in the diplo form but does not form chains. It is 

 stained by the usual dyes, often staining poorly at the ends. Stained 

 by Gram's method it is decolorized. The bacillus is non-motile. 



Cultivation. — It is easily cultivated upon the ordinary laboratory 

 media. Upon agar it forms, within twenty-four hours, transparent, 

 slightly fluorescent colonies which are round, raised, rather coarsely 

 granular, and show a tendency to confluence. 



Gelatin is not hquefied. 



Milk is coagulated. 



Upon potato, there is a thick yellowish growth. 



Upon dextrose media, there is acid formation, but no gas. 



The bacillus forms no indol in pepton solutions. 



Pathogenicity. — Corneal ulcers have been produced by inoculation 

 of guinea-pigs. 



BACILLUS OF DUCREY 



The soft chancre, or chancroid, is an acute inflammatory, destructive 

 lesion which occurs usually upon the genitals or the skin surrounding 

 the genitals. The infection is conveyed from one individual to an- 

 other by direct contact. It may, however, under conditions of surgical 

 manipulation, be transmitted indirectly by means of dressings, towels, 

 or instruments. 



The lesion begins usually as a small pustule which rapidly ruptures, 

 leaving an irregular ulcer with undermined edges and a necrotic floor 

 which spreads rapidly. It differs clinically from the true or syphihtic 

 chancre in the lack of induration and in its violent inflammatory 



