Physiology of Microbes. 29 



induction currents have been studied. This action. 



however, is but little known ; in the case of continu- 

 ous currents it is necessary to take into account the 

 electrolysis which separates the acids from the bases 

 and transfers these new molecules to the two poles. 

 The acid reaction of the positive pole is opposed to 

 microbic pullulation at this point; the alkalinity of 

 the negative pole is less energetic in its action. The 

 current may act upon the germ itself and interfere 

 with its multiplication, especially when strong cur- 

 rents are employed. It is not inadmissible to hope 

 that, the influence of electricity becoming better 

 known, its effects may some day be utilized in the 

 treatment of infectious diseases. 



3. Chemical influences. — The exhaustion of the nu- 

 tritive medium, accumulation of residual products, 

 excess of alkalinity and more especially of acidity, 

 oppose and may even arrest the multiplication of 

 germs. 



Certain chemical substances exert toxic effects upon 

 microbes, this toxicity varying with the microbic 

 species concerned. The rational application of this 

 action constitutes the basis of antisepsis from which 

 hygiene and medicine have already derived great 

 profit. 



4. Physiological influences. — "When several microbic 

 species occur in the same place they may oppose each 

 other and then a veritable struggle for existence en- 

 sues. From this concurrence may result the annihila- 

 tion of the least favored species; the medium, the 

 number of germs, and various other circumstances 

 may intervene here. In putrefactive media in which 



