MARINE BIOLOCxICAL STATION AT PORT ERIN. 243 



is, proportionately, considerably less than that of the 

 copper. 



" 6. In the Falmouth oysters containing an excessive 

 amount of copper, we find that much of the copper is 

 certainly mechanically attached to the surface of the body, 

 and is in a form insoluble in water, probably as a basic 

 carbonate. In addition to this, however, the Falmouth 

 oyster may contain a much larger amount of copper in its 

 tissues than does the normal colourless oyster. In these 

 Falmouth oysters the cause of the green colour may be 

 the same as in the green American oysters. 



"7. The Colon group of bacilli is frequently found in 

 shellfish, as sold in towns, and especially in the oyster ; 

 but we have no evidence that it occurs in Mollusca living 

 in pure sea-water. The natural inference that the presence 

 of the Colon bacillus invariably indicates sewage contamina- 

 tion must, however, not be considered established without 

 further investigation. 



" 8. The Colon group may be separated into two divisions 

 — (1) those giving the typical reactions of the Colon bacillus, 

 and (2) those giving corresponding negative reactions, and 

 so approaching the typhoid type ; but in no case was 

 an organism giving all the reactions of the B. typhosus 

 isolated. It ought to be remembered, however, that our 

 samples of oysters, although of various kinds and from 

 different sources, were in no case, so far as we are aware, 

 derived from a bed known to be contaminated or suspected 

 of typhoid. 



" 9. Consequently, as the result of our investigations, 

 and the consideration of much evidence, both from the 

 oysters growers' and the public health officers' point of 

 view, we beg to recommend : — 



" (a) That the necessary steps should be taken to 

 induce the oyster trade to remove any possible 



