32 



Prof. R. Boyce and Dr. W. A. Herdman. 



dealing with what we described a couple of years ago as the green 

 leucocytosis in the American oyster. Many papers, to which we do 

 not refer, have appeared dealing with other kinds of green oysters, 

 but they do not affect our present subject. 



In January, 1896,* we referred briefly to what appeared to be an 

 inflammatory condition, accompanied by a pale chalky-green colour, 

 which we found in some American oysters relaid at Fleetwood, on 

 the Lancashire coast; and at the Liverpool meeting of the British 

 Association, last September, in discussing various kinds of greenness 

 in oysters, we referred to this diseased condition, in the following 

 terms : — 



" There is, however, a pale greenness (quite different in appear- 

 ance from the blue-green of the " Huitres de Marennes ") which we 

 have met with in some American oysters laid down in this country, 

 and which we regard as a disease. It is characterised by a leuco- 

 cytosis, in which enormous numbers of leucocytes come out on the 

 surface of the body, and especially on the mantle. The green 

 patches visible to the eye correspond to accumulations of the leuco- 

 cytes, which in mass have a green tint. These cells are granular 

 and amoeboid. The granules do not give any definite reaction 

 with the aniline stains, and, so far, we have not made cut their 

 precise nature." 



Finally, towards the end of last year, in the ' Supplement to the 

 Twenty-fourth Annual Report of the Local Government Board,' Dr. 

 Bulstrode corroborated our statement as to the presence of the pale 

 green disease from the examination of specimens from Truro and 

 Falmouth. Dr. Thorpe stated in the same Report that he had found 

 that some green oysters from Falmouth, f sent to him for examina- 

 tion by Dr. Bulstrode and Mr. R. Vallentin, contained notable 

 amounts of copper, in some cases as much as 0"02 grain per oyster, 

 while the amount normally present is only 0'006 grain. 



Dr. Charles Kohn has kindly, during the last year or so, made a 

 number of analyses for us of different kinds of oysters — " natives," 

 " Marennes," Dutch, and American — and whereas in most of these 

 he has found the copper to be present only in small quantities, on 

 the average agreeing well with the amount (0 006 grain) usually- 

 stated as present in the tissues of the normal healthy oyster, in some 

 green Americans which we gave him recently for the purpose he has 

 found a very much larger amount of copper. These circumstances 

 induced us to reopen, in our investigations, the question of copper in 

 certain green oysters, with the results that are detailed below. 



* Keport for 1895 on the Lancashire Sea-Fisheries Laboratory (' Trans. Biol. 

 Soc.,' Liverpool, vol. 10, p. 158). 



f Obtained from a creek, which is locally supposed to bring down copper, and 

 the water of which was found on analysis to contain gome copper. 



