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NOTE ON THE OLIGODYNAMIC ACTION OF 

 COPPER UPON CERTAIN ORGANISMS. 



By W. A. Herdman. 



In connection with the investigations upon copper in 

 certain oysters and upon the pollution of certain oysters 

 by sewage, and so possibly by disease germs, which were 

 discussed fully in these Reports a few years ago, it may 

 be of interest to put on record now the recent remarkable 

 results that have been obtained in America, and else- 

 where, in destroying intestinal bacteria by means of 

 exceedingly minute traces of metallic copper. 



The botanist C. von Nageli seems first to have 

 observed, some time in the eighties, that even the copper 

 dissolved by distilled water during its passage through the 

 copper still might have a toxic effect upon certain plants. 

 He then experimented with water in which copper coins 

 had been placed, and determined, for example, that one 

 part of copper in about a thousand million parts of water 

 is poisonous to some species of the water plant Spirogyra. 

 Other investigators, both in Germany and the United 

 States, have since extended the experiment to the action 

 of copper upon bacteria and upon protozoa. They used 

 copper foil in the water, and found that Bacillus typhi 

 was especially sensitive, and that at a temperature of 

 35° to 40° C. the toxic effect was manifested in one hour. 

 Pharmacologists as well as biologists have recognised the 

 importance of these facts, and their possible application 

 to the treatment of disease. Copper, while being 

 exceedingly toxic to micro-organisms and certain 

 parasites, is comparatively harmless to man. Professor 

 Cushing (1899) says : — " Copper thus seems to have a very 



