78 MAUD MASON OBST 



which was markedly irregular and which permitted no compari- 

 son with any other sample. 



The contents of three individual gall bladders, collected on 

 different dates, were also tested. The ratios of inhibition (see 

 table, (f)) for any one organism on the three agars are nearly 

 uniform and on the individual bile agar the different strains 

 showed only a slight variation. 



A comparison of the average inhibitive action of each sample 

 of bile upon the different strains of organisms shows a vari- 

 ation from 2.4 to 3.8, and for the freshly collected bile a ratio of 

 approximately 2.4 for all strains. 



CONCLUSIONS 



In these experiments lactose bouillon used as a substitute for 

 lactose peptone ox-bile permitted the development of about twice 

 as many B. coli from water as the bile medium. 



Lactose bouillon costs less in money and labor. The difficulty 

 of obtaining pure, fresh bile puts it almost out of the reach of 

 many workers. The stored bile is proved to show progressive 

 deterioration. Lactose bouillon can be prepared when desired 

 and can be made more uniform. It need contain no precipitate 

 to clog the inner tube or to affect the activity of the organism. 



REFERENCES 



Hall, I. W. and Nicholls, F. (1914) Earlier indications of gas formation 



by coliform organisms; with description of a modified fermentation 



tube. Centr. f. Bakt., Abth. I, Orig. 75, 140. 

 Jackson, D. D. (1906) A presumptive test for B. coli. Biological Studies 



by the Pupils of W. T. Sedgwick. U. of C. Press., 292. 

 Jordan, E. O. (1913) The inhibitive action of Bile upon B. coli. Jour. Infect. 



Dis., 12, 326. 

 Sawin, L. R. (1907) Experience with lactose bile medium for the detection 



of B. coli in water. Jour. Infect. Dis., Supp. No. 3, 33. 

 Smith, T. (1893) The fermentation tube, with special reference to Anaerobiosis 



and gas production among bacteria. The Wilder Quarter-Century 



Book. Ithaca, N. Y. 187. 

 Smith, T. (1895) B. coli communis. Amer. Jour. Med. Sci., N. S. 110, 283. 

 Weston, R. S. andTarbett, R. E. (1907.) Comparative results obtained by 



the use of lactose bile and dextrose broth media for the detection of 



B. coli in water. Jour. Infect. Dis., Supp. No. 3, 39. 



