212 SAMUEL C. PRESCOTT 



(intestinal) it was found that 25 out of a total of 47 cultures isolated 

 gave typical colon characteristics, while several more failed in but 

 a single test. Nine cultures were rejected. 



The organisms thus obtained, together with a number of cultures 

 of supposed B. acidi lactici from various laboratories, were then 

 subjected to actual comparison, side by side with 22 cultures of 

 B. coli isolated directly from feces, or from waters known to be 

 sewage-polluted. The fecal bacteria were obtained by preliminary 

 cultivation of the fecal matter in dextrose broth for four to eight 

 hours, and then plating in great dilution on litmus lactose agar. 

 It was found that, if this procedure was used, a nearly pure culture 

 of B. coli resulted; but if the preliminary cultivation was prolonged, 

 the colon bacilli were likely to be overgrown by streptococci, and 

 frequently were entirely lost. 



In the first series, cultures from the sources mentioned below 

 conform to the following characteristics: Motile, non-spore-forming 

 bacilli producing turbidity in nutrient broth, characteristic growth 

 on gelatin plate, surface and needle-growth in gelatin stab; growth 

 on potato and in closed arm of the fermentation tube; grow at 

 body temperature and are facultative anaerobes; do not liquefy 

 gelatin, casein, or blood serum; produce gas in dextrose, lactose, 

 and saccharose broth ; nitrate is reduced, indol formed ; milk becomes 

 acid and curdles. 



Five cultures of B. acidi lactici from the University of Chicago. 



Four " from cornmeal. 



Six " " buckwheat. 



Five " " barley. 



Three " " bran. 



One culture from flour. 



One " " breakfast food. 



These cultures give identical results and can in no way be differ- 

 entiated from the 18 cultures mentioned below, which are of undoubted 

 intestinal origin. 



Ten cultures from feces. 



Two the Mystic River. 



One ' " Neponset River. 



One ' injected peritoneum. 



One ' pool under snow. 



One ' driven well in brewery. 



One ' polluted brook. 



One ' meadow at Framingham. 



