30 



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



In certain cartilaginous fish there is a combination of both of 

 these arrangements of tubes, from the dentine and from the sur- 

 face, and sundry other apparently anomalous conditions are met 

 with. 



But if the views advocated in this paper be accepted, all diffi- 

 culty in accounting for these arrangements, very difficult to explain 

 from any teleological standpoint, disappear, for they become merely 

 slight variations or arrests at different stages of a process common to 

 all enamels during their formation. 



On a Green Leucocytosis in Oysters associated with the 

 presence of Copper in the Leucocytes." By Rubert 

 Boyce, M.B., Professor of Pathology in University College, 

 Liverpool, and W. A. Herdman, D.Sc, F.R.S., Professor of 

 Zoology in University College, Liverpool. Received 

 July 9, 1897. 



In the course of an investigation upon oysters under normal and 

 abnormal conditions, upon which we have been engaged for the last 

 two years, and upon which we propose to submit to the Society a 

 detailed memoir during next session, we have come upon a pheno- 

 menon which we regard of such considerable importance that we 

 desire to publish a brief record of our observations and experiments, 

 as we believe they may prove of interest to other biologists who are 

 engaged in work on the micro-chemistry of the cell. The phe- 

 nomenon we have now to describe is the presence of large quantities 

 of copper in certain green leucocytes found in a diseased condition 

 of the American oyster. The oysters suffering from this leucocytosis 

 are always more or less green, but must not be confounded with 

 ordinary green gillecl oysters, where the colour is due to a totally 

 distinct cause. 



History. 



Green oysters have been known from an early period, and there 

 are various historic cases on record* of people having been poisoned 

 by eating green oysters, and of the oyster merchants being put upon 

 trial because of the deleterious nature of their goods. Periodically 

 green oysters have been suspected or convicted of being coloured 

 with copper, and just as often it has been proved by competent 

 authorities that copper has nothing whatever to do with the green 

 colour. This difference of opinion in the past has undoubtedly been 



* An interesting historical survey of the subject up to 186B, was given by the 

 late Mr. Arthur O'Shaughnessy, in the ' Annals and Mag. Nat. Hist.,' ser. 3, 

 vol. 18. 



