QUANTITATIVE BACTERIOLOGICAL ANALYSIS. 25 



the bacteria to be studied. When development had taken 

 place, the plates were placed in salt solution and the current 

 allowed to pass. It was found that the positive pole was more 

 bactericidal than the negative pole, and that the effect depended 

 on the intensity and duration of the current. A current of 50 

 milliamperes passing for a quarter of an hour did not kill the 

 Staphylococcus pyogenes aureus, but a current of 60 milliamperes 

 killed it at once. In order to kill a spore-bearing bacillus a 

 current of 200 to 230 milliamperes was required for two hours. 

 The bactericidal power of the positive pole appeared to be due 

 to the chlorine liberated from the salt solution. The effect of 

 the current, as in the previous experiments, was due to a chemical 

 and not to a physical* action. According to Fischer strong 

 electric currents are fatal to bacteria, their protoplasm being 

 killed, although some of the deleterious effect may be due to 

 the electric dissociation of the media and to the increase of 

 temperature caused by the current. 



