THE SIGNIFICANCE OF B. CO LI IN WATER. 79 



each case a single centimeter sample was first incubated 

 in Parietti broth, and if no growth occurred, larger samples 

 of half a liter or a liter were examined. Colon bacilli 

 were found in all the samples examined; and the patho- 

 genicity varied independently of the source of the water. 1 

 The author concluded that "the so-called Bacterium 

 coli may be found in waters from any source, good or bad, 

 if only a sufficiently large quantity of the water be taken 

 for analysis." In the first place it should be noted that 

 the characters used by this investigator for defining the 

 "so-called Bacterium coli" were absolutely inadequate. 

 He classed under that head all bacilli of medium size, 

 which formed grapevine-leaf colonies on gelatin and 

 gas in sugar agar, which were more or less motile, or 

 rarely non-motile, and which were decolorized by the 

 Gram method. As regards coagulation of milk and 

 formation of indol, "the bacteria isolated differed." In 

 the second place it is difficult to see how the author could 

 possibly have believed that his experiments proved the 

 isolation of the colon bacillus to be "useless as an aid in 

 the sanitary examination of water," as the title of the 

 paper runs. Even his own work furnishes strong evi- 

 dence to the contrary. In 24 of the 26 samples from bad 

 sources, he isolated his imperfectly defined colon bacilli 

 from i c.c. of the water, while in only 8 of the 30 samples 

 of good waters could he find such organisms in that 

 quantity. 

 Of a series of 47 cultures of actic-acid bacteria 



1 Confirmed by Savage (Savage, 1903,. 



