372 



SCIENCE. 



[N. S. Vol. XV. No. 375. 



The Distribution of B. coli comw,unis in 

 Natural Waters: C. E. A. Winslow, 

 Massachusetts Institute of Technology, 

 Boston, Mass. 



The work of certain observers has shown 

 that organisms apparently identical with 

 B. coli communis are found widely distrib- 

 uted in nature. The problem for the bac- 

 teriologists, and especially for the sanita- 

 rian, becomes, then, a quantitative one. 

 Even if this organism does occur in vari- 

 ous places in the outside world, may it not 

 still be true that it thrives only, or at least 

 most abundantly, in the intestine of the 

 higher vertebrates, and that an overwhelm- 

 ing proportion of the individual represen- 

 tatives of the species occurs in that habi- 

 tat? May it not be true then that while 

 the Bacillus coli is found at times in un- 

 polluted waters, its presence, constantly, or 

 in numbers, is still characteristic of sewage 

 pollution? As a preliminary contribution 

 to this question a number of presumably 

 unpolluted waters in the neighborhood of 

 Boston have been examined for the Bacil- 

 lus coli. In each case one centimeter of 

 the water was incubated in dextrose broth 

 and one hundred cubic centimeters were 

 incubated with the addition of phenol- 

 glucose broth. From the one hundred 

 cubic centimeter bottles, after incubation, 

 dextrose broth was inoculated, and from all 

 dextrose tubes showing gas, litmus-lactose- 

 agar plates were made. Three characteris- 

 tic colonies were fished from each reddened 

 litmus-lactose-agar plate, and subcultures 

 inoculated. Only those which gave the 

 following reactions were considered as B. 

 coli: The fermentation of dextrose broth 

 with the production of gas in twenty-four 

 hours; the fermentation of lactose in the 

 litmus-lactose-agar plate, with distinct red- 

 dening in twenty- four hours; the coagula- 

 tion of milk in twenty-four hours ; the pro- 

 duction of nitrite from nitrates in twenty- 

 four hours ; the production of indol in pep- 



tone solution in three days; the formation 

 of an abundant growth covering nearly the 

 whole surface of the agar streak in twenty- 

 four hours, later becoming whitish and 

 cheesy, but not stringy to the needle; the 

 formation of round or oval white colonies 

 in the gelatin shake culture, often with 

 gas bubbles, with no liquefaction of the 

 gelatin in seven days. The use of one hun- 

 dred cubic centimeters appears in these ex- 

 periments to have increased the proportion 

 of dextrose and lactose fermenting organ- 

 isms, but not of colon bacilli. The investi- 

 gation included the study of seventy-nine 

 samples of water. The results lead to the 

 conclusion that the colon bacillus is so rare 

 in normal unpolluted waters as to be found 

 infrequently when single centimeters of 

 the water are examined. The presence of 

 this organism, constantly, or in a majority 

 of cases, in one cubic centimeter, may still 

 be assumed to be due to the entrance of 

 some polluting substance. 



Preliminary Observations on B. coli com- 

 munis from Certain Species of Animals: 

 Vbranus a. Moore and Floyd R. 

 Weight, Cornell University, Ithaca, N.Y. 

 A study has been made of B. coli com- 

 munis found in a single place in each of 

 the large and small intestines of nine 

 horses, eleven cattle, eight sheep, four 

 swine, eight dogs and six chickens. This 

 organism was not found in the intestines 

 of six frogs, two young and one old rabbit. 

 It had previously been found in several 

 rabbits. These animals were all supposed- 

 ly healthy and, excepting the frogs and 

 rabbits, were for the greater part killed for 

 dissection or food. Cultures in bouillon 

 from six colonies from the gelatin plate 

 cultures from each of the large and small 

 intestines were made; these were replated, 

 and from the colonies which developed on 

 them subcultures were made and studied 

 on gelatin, agar and potato: in milk,. 



