204 DYSENTERY, HOG AND CHICKEN CHOLERA. 



Pathogenesis. In man a subacute conjunctivitis is produced 

 by this bacillus. Animal inoculation has been negative. 



BACILLUS OF DUCREY. 



History. Ducrey, in 1889, in the discharges from chan- 

 croids and their concomitant buboes was able to demonstrate 

 these bacilli constantly. 



Morphology and Staining. This bacillus is extremely small, 

 scarcely half a micron in width. In length it measures from 

 one to two micra. It occurs in short chains, or in parallel 

 rows, or in irregular groups. In pus these bacilli are usually 

 found in pus-cells. They are stained readily but irregularly 

 by the ordinary aniline dyes, the poles staining more deeply. 

 By Gram's method they are decolorized. 



Biologic Character. B. Ducrey is non-motile, non-flagel- 

 lated, and non-spore bearing. It is artificially grown with 

 great difficulty. The best growths have been obtained on 

 agar containing human blood. Growths on coagulated blood, 

 agar, and rabbit's blood, and even serum agar have been suc- 

 cessful. The pus obtained directly from the bubo with a 

 sterile needle is placed immediately on the culture-medium. 

 The material obtained by scraping from the deeper portions 

 of the chancroid may be used. Small transparent gray firm 

 colonies usually appear after forty-eight hours. 



Pathogenesis. Successful inoculation has been practised on 

 man by Besan9on and others. Animal inoculation has been 

 negative. 



QUESTIONS. 

 Dysentery. 



When and by whom was the Bacillus dysentericse discovered and described ? 

 What is its morphology ? 

 How does it stain ? 

 Give its principal biologic characters. 



How does it grow on agar? On potato ? On bouillon ? In litmus milk ? 

 Does it produce indol? 



Does its serum have an agglutinating power ? 



What is the effect of an intraperitoneal injection in animals? Of a sub- 

 cutaneous injection? 



