CHAPTER XIII. 



NON-SPORING BACILLI. 



THE COLON-TYPHOID-DYSENTERY GROUP. 



THIS is a large group, which includes the colon bacillus 

 and its allies ; the typhoid bacillus ; paratyphoid bacilli ; 

 dysentery bacilli and allies ; and Bacillus faecalis alcaligenes. 



Closely related to the group (but not properly within it) 

 are the B. lactis aerogenes, B. mucosus capsulatus (Fried- 

 laender's bacillus), and B. proteus. 



All the members of the group are bacilli and are very 

 similar morphologically, but exhibit minor differences 

 insufficient to permit of accurate diagnosis from mor- 

 phology alone. All are non-sporing, non-liquefying of 

 gelatin, Gram-negative, and grow well at room and body 

 temperatures on artificial media. 



They are distinguished from one another by a careful 

 cultural and biological study, to wit : reactions in special 

 media (e.g. the FL-AG-IN-AC group of reactions : fluor- 

 escence with neutral red, acid and gas with lactose, indol 

 with peptone water, acid and clot in litmus milk) ; motility 

 and flagella ; and reactions with, specific immune sera 

 (chiefly agglutination). 



Bacillus Coli Communis is a name which stands for a 

 group of organisms, one member of which was first described 

 by Buchner in 1885. The one taken as a type of the group 

 was obtained from the stools of a breast-fed infant, and 

 was described by Escherich in 1886 as the Bacterium coli 

 commune. It is now usually designated B. coli (Escherich). 



It is widely distributed in nature and has been isolated 

 from air, water, and soil, but is found most abundantly and 

 constantly in the intestinal tract of man and of many of 

 the higher animals, from which habitat it probably finds 

 its way into soil, water, and air. Its chief characteristics 

 are : short plump rod, 2 to 4 micra long and 0-4 to 0-7 micron 

 broad (very short oval and coccus-like forms are found. 



