194 Malachite-Green and the Physiological Activity o/B. coli. 



soil, mineral media, etc., develops the power of slime production in an 

 extraordinary manner (2). 



Bacillus coli at all times shows a tendency to grow into filaments, though 

 not of very great length. In the course of some experiments, now proceeding, 

 in which methylene-blue is substituted for malachite-green, the development 

 of long filaments of similar character to those produced in Coli A has been 

 noticed in several cases. 



This peculiar type of growth, together with the production of " gum," seems 

 to point strongly to the development of Bacillus coli from a class of well-known 

 soil bacteria, and, in fact, I have been able to train some of these bacteria to 

 a very close resemblance to the new type developed from Coli A under the 

 action of malachite-green. 



I am indebted to the kindness of Dr. Vincent, Senior Physician to and 

 Director of the Bacteriological Laboratory of the Infants' Hospital, Vincent 

 Square, for the photograph of Coli A here reproduced. 



EEFERENCES. 



(1) Eevis, ' Cent. f. Bakt.,' 1911, vol. 31, Abt. II, p. 1. 



(2) Revis, ' Cent f. Bakt.,' 1910, vol. 26, Abt. II, p. 161. 



