84 LABORATORY GUIDE IN BACTERIOLOGY 



Perform these tests with all the organisms of the 

 intestinal group, and make control tests in sterile Dun- 

 ham's solution. 



4. Special study C. Make capsule stain of B. 

 lactis acrogenes from 24-hour-old milk-cultures. (For 

 method see p. 77.) 



The study of B. coll is of special importance in con- 

 nection with bacteriological analyses of water (see Chap. 

 XXIV). The presence of this organism in large num- 

 bers indicates sewage contamination, and consequently 

 the danger of an admixture of pathogenic bacteria such 

 as B. typhosus and B. dysenteriae. 



EXERCISE II. STUDY OF SUBGROUP II 

 THE HOG-CHOLERA, B. ENTERITIDIS, OR INTERMEDIATE GROUP 



Use great care in handling members of this group. 



Inoculate agar-slants from stock-cultures of B. 

 cholerae suis (bacillus of hog-cholera), B. enteritidis 

 (Gartner's bacillus), and B. paratyphosus (two strains). 

 REFERENCES 

 B. cholerae suis: 



Moore, The Pathology of Infectious Diseases of Animals. 



McFarland, Textbook of Bacteriology. 

 B. paratyphosus: 



Buxton, Journal of Medical Research, 1902, Vol. VIII, p. 201. 



Wells and Scott, Journal of Infectious Diseases, 1904, No. i. 



Gushing, Johns Hopkins Hospital Bulletin, 1900, p. 156. 



Durham, Journal of Experimental Medicine, Vol. V, p. 353. 



1. Routine study. Observe particularly the bluish- 

 green coloration of the cream-ring in litmus milk, and 

 make test for indol. 



2. Special study A. Inoculate plain sterile milk with 

 B. cholerae suis. After 8-10 days a clearing of the milk 



