86 ABSTRACTS 



per cent dried bile, 5 per cent dried bile, 2 per cent dried bile, and lactose 

 broth, showed the presence of B. colt at first in all media, later only in 

 media containing 5 per cent or less of dried bile, and finally in lactose 

 broth alone. 



A water heavily polluted with feces tested in the same manner showed 

 gas in one higher dilution in the 10 per cent dried bile and in whole bile 

 than in the other media containing less amounts of ox gall. This 

 water was so bad in appearance that a sanitary examination would 

 have been unnecessary and therefore represents an exaggerated case. 



For these somewhat contradictory results the following explanation is 

 offered. It is believed that they are really not contradictory but are 

 typical of the results which, being reported by different workers dealing 

 with different material for test purposes, have confused the issue for 

 some time. 



The intestine is not filled with bile but bathed with it and the environ- 

 ment of intestinal organisms may be regarded as one of diluted bile. 

 It seems reasonable then to suppose that a test tube of diluted bile 

 offers a more favorable environment for these organisms than a test 

 tube of whole bile. Organisms which develop in the standard medium 

 do so in spite of the concentration of bile, and the weaker ones succumb. 



The view is offered that in testing highly polluted material where the 

 presence of organisms which will develop in the presence of lactose is 

 so great that there is danger of overgrowth of B. coli and the shutting 

 off of fermentation, the inhibiting property of bile toward non intestinal 

 organisms is desirable. 



Where the danger of overgrowth of B. coli is not great as in mildly 

 polluted samples, lactose broth may be as efficient and will probably 

 be more delicate. 



The danger in using lactose broth is not that too many organisms 

 will be included by the test, but that too many may be lost by over- 

 growth of others. 



The question which ought to engage the attention of sanitary analysts 

 is not "Shall we use bile or shall we use lactose?" but "How much bile 

 plus how much lactose?" 



The results of experimentation upon which this paper is based 

 indicate that a medium composed of 1 per cent peptone, 1 per cent 

 lactose, and from 2 to 5 per cent dried bile is much more delicate in de- 

 tecting intestinal organisms by the fermentation test than is our present 

 Standard medium, and is in the majority of cases more reliable than 

 lactose broth alone. 



A Chromogenic Bacillus. Frank L. Rector. 



This organism was isolated from water. It is a small rod with 

 rounded ends, measuring from two to four microns long by seven- 

 tenths of a micron wide. Occurs singly. Is motile. Stains evenly 

 and easily; is Gram negative. Forms no nitrites, and indol production 

 is doubtful. Coagulates milk in twenty-four hours. Forms gas in 

 glucose, saccharose and glycerin; no gas in lactose. Thermal death 

 point is 66°F. for ten minutes. 



