1891.] **d [Bache. 



through the false inference that I had drawn that, because the 

 electric current did not destroy protozoa of the kind with which 

 I w:ts dealing-, therefore bacteria would not he destroyed by it, 

 at least within the bounds compatible with human life or well 

 being. It seems, however, that vegetable protoplasm, at least of 

 the fungus kind, acts differently from animal protoplasm under 

 the influence of the electric current. After reading the results 

 of Dr. Griffiths, I gladly reverted to the intention with which I 

 had set out in my experiments, of being able to suggest means 

 by which bacilli forming a nidus in the human body could be 

 destroyed and water supplied to cities could be sterilized for 

 drinking purposes. 



The author to whom I have referred is Dr. A. B. Griffiths, Fel- 

 low of the Royal Society of Edinburgh. He remarks that the 

 full details of his experiments with electricity on bacteria are to 

 be found in Volume xv of the Proceedings of the Society. In 

 making the experiments he seems to have had no ulterior object 

 in view but the gaining of information as to what amount of cur- 

 rent would destroy certain micro-organisms. The wood-cut which 

 he gives at page 177 of his work, Micro-organisms, represents a 

 faraclaic, not a galvanic battery, as the generator of the electro- 

 motive force used in his experiments. At the beginning of mine 

 I used both the galvanic and the faradaic battery. The recep- 

 tacles in which Dr. Griffiths placed pure cultures of different 

 bacteria were simple, broad-based, short bottles, in which were 

 litted from top to bottom of each bottle a single loop of wire in 

 free electric liquid communication with the micro-organisms. lie- 

 does not in any case give the resistance in ohms of the media 

 employed in the cultures. 



The bacillus tuberculosis was killed by 2.16 volts, the bacterium 

 lactis by 2.26 volts, and the bacterium aceti by 3.24 volts. The 

 electric current was allowed to pass for ten minutes, and the 

 temperature of the laboratory during the experiments was 16 C 

 (60.8 Fah.). In another series of experiments, bacillus tuber- 

 culosis was killed by 2.16 volts, bacillus subtilis by 172 volts. 

 and bacterium allii by 3.3 volts. The current, as before, was 

 allowed to pass for ten minutes, and the temperature of the labor- 

 atory was 17 C. (62.6 Fah.). In the first series of experiments 

 no growths appeared from inoculation in fresh nutritive media, 

 after an incubation of twenty-five days, with the thermometer at 



PROC. AMER. PHILOS. SOC. XXIX. 135. E. PRINTED JUNE 1, 1891. 



