■201 



obtaiued by adding eith«>i' (•()])j)ei' coins, copper foil, or 

 salts of copper to water : when ('0])pei' foil is used 

 sutlicieut copper is dissolved bv the distilled water in 

 one to five iniinites lo kill i\\r ly]»li(>i(1 organisms witliin 

 two hours. 



" 7. A solution of (•(tj)|)(M' iiuiy lose iis ioxicily by 

 I lie )treeipitatioi) of llie copper as an insoluble salt or 

 compound, by its absorption by organic substances, or 

 by absorption by insoluble substances. 



" 8. The oligodynamic action of the copper is 

 dependejit n])nji 1(>mpcin(ui(\ as first ])oiufed oul by 

 Israel and Jvliugmanii. 



" [K The effects of oligotlyiiamic copper in the 

 |>uritiea1 ion of diinkiug water ai-i' in a quantitative 

 sense much like those of hltratioii, onlv the or^auisms 

 removed, like JL typJii and />'. roli, are completely 

 destroyed." 



Now if these results can be extended to the case 

 of marine shell-fish, it may be argued that if 

 the typhoid organism is killed in two hours by 

 distilled water in whi<di copper foil has been placed for 

 five minutes, a comparaiiv(dy simple measure of washing 

 ought to b(> sufficient to I'endei- contaminated oysters 

 innocuous. The importance of such a result is obvious. 

 It may be asked Avh}', consideiing the rather large amount 

 of copper that may be present in lli(> tissues of the oyster, 

 should the copper foil be necessary. It is known, how- 

 ever, to be the case that in the normal oyster the copper 

 (d' the blood is united with a urcttcid to foiin an orcauic 

 compound, haemocyanin, in such a way as to be unable to 

 exercise its toxic ])ro])ertics. \\ i> pidbablc that that is also 

 the ease in these abnormal green oysters which Professor 

 IJoyce and 1 investigated'' some years ago, and where we 



■■' ( )u 11 -I'lTii LoiU'oeytofii^ in C'vstors. I^roc. Rovul Society, vol. 

 Ixii., p, :J0 (1S',I7), 



