78 



a large excess of copper as compared with iron in the 

 green Oyster, as is evident from the analyses, the ratio 

 being I'l : 1 for the white and 1'8 : 1 for the green. 



' It is to be concluded, therefore, that the green colour 

 of these Oysters is coincident with the distribution of the 

 excessive quantity of copper present, and that the copper 

 is in consequence to be regarded as the cause of the 

 colour. The histo-chemical investigations of Boyce and 

 Herdman have amply confirmed this conclusion. 



' Further, this leucocytosis is not accompanied by a mere 

 redistribution of copper, but by an absolute increase of 

 the amount present in the body. 



' The deposition of copper in this manner is regarded by 

 Boyce and Herdman " as a degenerative reaction, due to 

 a disturbed metabolism, whereby the normal copper of 

 the hgemocyanin, which is probably passing through the 

 body in minute amounts, ceases to be removed, and 

 so becomes stored up in certain cells." The change 

 is comparable in kind to the accumulation of iron in 

 pernicious anaemia. 



' The increased quantity of iron present may also be due 

 to abnormal conditions of life, but a more accurate 

 localisation of the normal iron of the Oyster is necessary 

 before this can be decided. 



' This green leucocytosis has been observed by Herdman 

 and Boyce in other Oysters, including those of Falmouth, 

 and it is likely to be the real cause of their colour ; a 

 colour therefore due to copper as previously supposed, 

 but accompanied by a diseased condition. AVhetlier the 

 presence of copper in the water facilitates in any way the 

 development of the disease has not been determined ; 

 experiments made on keeping Oysters in very dilute saline 

 copper solutions give no affirmative results beyond a 

 certain amount of post-mortem green staining. 



