CHAPTER XX 



ANTAGONISM AMONGST BACTERIA 



That the chemical products of some species of microbes, 

 while acting inimically on the further multiplication of this 

 species, are not inimical to that of another species has been 

 proved by various observations, but it has also been proved 

 that an inimical action is undoubtedly exerted by the growth 

 of particular species on that of others. It is well known 

 that a number of species of bacteria can exist and thrive 

 under conditions under which other bacteria cannot so 

 exist ; take, for instance, the water bacteria, i.e., the bacteria 

 inhabiting common drinking water ; these are capable of 

 living and of multiplying on the very small amount of 

 nutritive material present in ordinary drinking water, nay, 

 micrococcus aquatilis and bacillus erythrosporus (Fliigge) 

 and others, as mentioned above, multiply even in distilled 

 water (Meade Bolton, Niessen, Percy Frankland) ; whereas 

 numerous species of bacteria rion-habitually in water cannot 

 do so under the same conditions ; therefore the water 

 bacteria will persist and even multiply, whereas others added 

 to the water, or accidentally finding entrance into the water, 

 will perish, some sooner, some later. Numerous observa- 

 tions have been put on record by Meade Bolton, Wolffhiigel 

 and Riedel, and others to show in what way and to what 



