316 



THE ALCA LIGENESD YSEN TER Y T YPHOID 



agglutinins from the .Shiga bacillus, and Lentz 1 showed that the Shiga 

 bacillus did not ferment mannite; the Flexner bacillus ferments this 

 alcohol with the production of acid. Later intensive studies of bacil- 

 lary dysentery bacilli by Park and Dunham, Hiss and Russell, and 

 others confirmed the work of the earlier observers and added several 

 strains to the group, which differ from the Shiga and Flexner strains 

 both with respect to their specific agglutinating powers and their 

 cultural reactions. The principal cultural reactions of the more 

 prominent Gram-negative intestinal bacteria, including not only the 

 pathogenic organisms but the habitually parasitic organisms as well, 

 follow : 



Legend: carbohydrate solutions: = no fermentation, + = acid produced, g = gas 



produced. 



milk: = no fermentation, alkaline reaction, = initial acidity, terminal 

 alkalinity, + = acid, c = coagulation, p = peptonization. 



Morphology. The morphology of the members of the dysentery 

 group of bacilli is practically identical; they are medium-sized, rod- 

 shaped organisms, measuring from 0.8 to 1 micron in diameter, and 

 from 1.5 to 3 microns in length. They have rounded ends and occur 

 singly or in pairs, rarely in short chains. Frequently elongated 

 somewhat irregular involution forms are found in old broth cultures. 

 The bacilli are non-motile (except the "Rosen" strain, which is slug- 

 gishly motile), possess no flagella, form no capsules and produce no 

 spores. They stain fairly readily with ordinary anilin dyes; frequently, 



Zeit. f. Hyg., 1902, p. 559. 



