May 26, 1905.] 



SCIENCE. 



805 



The classical experiments conducted by 

 Nageli during the eighties for determining 

 the toxicity of solutions of copper pro- 

 duced by placing clean copper coins in dis- 

 tilled water for several days, on Spivogyra, 

 a filamentous alga, was reviewed. 



It was pointed out that Nageli observed 

 that the effects produced by the copper 

 solution so obtained, on Spirogyra, differed 

 from those due to ordinary chemical poison- 

 ing, and that in describing the supposedly 

 distinctive effects of such minute traces of 

 copper in solution (he having estimated 

 that approximately 1.3 parts of copper to 

 1,000 million parts of water would kill 

 Spirogyra), he used the term 'oligody- 

 namische,' meaning thereby the force or 

 action exerted by a small quantity of sub- 

 stance. 



Reference was made to the very great 

 importance of Nageli 's discovery from a 

 scientific point of view, and the statement 

 made that while researches of the kind con- 

 ducted by Nageli and other writers since 

 his time had an important bearing on 

 pharmacology, it was not, however, until 

 the publication of the bulletin on 'A 

 Method of Destroying or Preventing the 

 Growth of Alg£e and Certain Pathogenic 

 Bacteria in Water Supplies,' by Moore and 

 Kellerman nearly a year ago, that the 

 very great practical significance of work 

 along these lines became apparent and gen- 

 eral interest was aroused in the subject. 



Since last fall the author has carried on 

 a number of series of experiments with the 

 particular end in view of testing the effi- 

 ciency of metallic copper for destroying 

 typhoid and colon bacilli. The technique 

 was described, and the following conclu- 

 sions drawn from the results obtained as 

 well as those given by other writers: 



1. Certain intestinal bacteria, like colon 

 and typhoid, are completely destroyed by 

 placing clean copper foil in water contain- 

 ing them, or by adding the organisms to 



water -previously in contact with the foil. 



2. The toxicity at water to which either 

 copper coins or copper foil has been added 

 is probably due to the solution of some 

 salt of copper, as first suggested by Nageli. 



3. The copper is probably in the form of 

 a crystalloid rather than that of a colloid, 

 as it has the property of permeating the 

 cell walls and organized cell-contents of 

 both animals and plants, thereby producing 

 the toxic effects. 



4. While the effects produced by the 

 oligodynamic action of copper are appar- 

 ently dift'erent from those of true chem- 

 ical poisoning, the difference is probably in 

 degree only and not in kind. 



5. Certain lower organisms, including 

 both plants and animals, possess a specific 

 sensitiveness to minute quantities of cop- 

 per and other substances as well, and it 

 has been shown that they are not restored 

 on transferring them to water free from 

 oligodynamic properties. 



6. Oligodynamic solutions of copper are 

 obtained by adding copper coins, copper 

 foil, or salts of copper to water. When 

 copper foil is allowed to remain in distilled 

 water from one to five minutes sufficient 

 copper is dissolved by the water to kill 

 typhoid organisms witliin two hours. 



7. A solution of copper may lose its 

 toxicity by the precipitation of the copper 

 as an insoluble salt or compound, by its ab- 

 sorption by organic substances, or by ad- 

 sorption by insoluble substances. 



8. The oligodynamic action of the copper 

 is dependent upon temperature as first 

 pointed out by Israel and Klingmann. 



9. The effects of oligodynamic copper in 

 the purification of drinking water are in a 

 quantitative sense much like those of filtra- 

 tion, only the organisms removed, like B. 

 typhi and B. coli, are completely destroyed. 



Observations on Cohimhium and Tantahim: 

 Dr. Edgar F. Smith. 



