XX] ANTAGONISM AMONGST BACTERIA 529 



latter has not much chance of growing and multiplying ; 

 and hence in any part of an animal dead of anthrax, at 

 first full of the bacillus anthracis, as soon as putrefaction 

 has actively set in, the anthrax bacilli will be gradually 

 killed off by the saprophytes, so that such material becomes 

 deprived of producing anthrax infection. The same obtains 

 with other highly specialised bacteria, e.g., the streptococci, 

 the typhoid fever bacillus, and others. While this process 

 of killing off of the more specialised and less assimilative 

 bacteria by the more rapidly growing and more assimilative 

 bacteria is essentially a survival of the fittest in the struggle 

 for existence, there is another factor to be considered that 

 not immaterially helps to bring about that result : it is the 

 inimical influence the chemical products of the saprophytic 

 bacteria have on the more sensitive and more highly speci- 

 alised pathogenic bacteria. If, for instance, a filtered solution 

 is made of a putrid albuminous substance, the putrefactive 

 bacteria being all removed, and of this solution a consider- 

 able amount is added to an otherwise favourable nutritive 

 material, e.g., alkahne broth, it will be found that this 

 mixture is unfavourable for the growth of some species, in 

 some cases more than in others. To the same class of 

 inimical influences belongs the influence of fscal matter on 

 various species of bacteria, e.g., anthrax bacilli, cholera 

 spirilla, typhoid fever bacillus investigated by Kitasato. 

 His results on the death of cholera spirilla in faecal matter 

 are instructive. They are published in the Zeitschrift f. 

 Hygiene, v. p. 487. 



Of a similar character are the observations recorded by 

 Garre {Correspond, f. schweizer. Aerzte, xvii. 1887), who 

 showed that nutritive gelatine which has served already for 

 the growth of bacillus fluorescens putidus — a common sapro- 

 phyte in water and putrid fluids — is no more capable of 



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