738 



SCIENCE. 



[N. S. Vol. VIII. No. 204. 



in all respects. It will be remembered that 

 in our Liverpool Report (1896) we described 

 the occurrence of the tj'phoid organism after 

 various intervals of time in oysters which 

 we had experimentally infected with typhoid 

 material. To that report* we may refer 

 also for a discussion of the results of wash- 

 ing infected oysters in a running stream of 

 sea- water, and for a statement of the dim- 

 inution of the number of typhoid organisms 

 as the time of inoculation recedes. In our 

 Ipswich paper f we had shown that oysters 

 were able to live, and did live, under very 

 impure conditions, and were able to make 

 use of sewage matter as food. We also 

 demonstrated (in 1895) by experiments that 

 those laid down in the proximity of drains 

 contained far more micro organisms than 

 such as were some distance off in purer 

 water. Finally, in last year's report at 

 Toronto, J we gave an account of the un- 

 healthy condition of certain green oysters, 

 of the association of the color with a leuco- 

 cytosis, and of the presence of copper in the 

 leucocytes. § 



As the result of these various lines of 

 investigation, and of the examination of 

 oysters alive under both natural and arti- 

 ficial conditions on various parts of the 

 British, French, Dutch and Italian coasts, 

 we have arrived at the definite conclusions 

 as to their natural history, chemistrj^ and 

 bacteriology, which are detailed below ; 

 and to which we have ventured to add 

 some recommendations as to administrative 

 and public health questions. We are con- 

 vinced that all that is necessary in order 

 that the oyster may be restored to its proper 

 position in public estimation as a most use- 

 ful, delicate and nutritious food-matter is 

 that shellfish importing, growing and lay- 



* Brit. Assoc. Rep., Liverpool Meeting, 1896, p. 

 663. 



t lUd., Ipswicli Meeting, 1895, p. 723. 

 Xlbid., Toronto Meeting, 1897, p. 363. 

 ^See also Proe. Roy. Sac, Vol. LXII., p. 30. 



ing shall be conducted under proper super- 

 vision, and that the grounds and waters 

 chosen for the purpose should be inspected 

 and licensed by duly qualified scientific 

 authorities. 



CONCLUSIONS. 



1. There are several distinct kinds of 

 greenness in oysters. Some of these, such 

 as the green Marennes oysters and those of 

 some rivers on the Essex coast, are healthy ; 

 while others, such as some Falmouth oys- 

 ters containing copper and some American 

 oysters re-bedded on our coast and which 

 have the pale green leucocytosis we de- 

 scribed in the last report, are not in a 

 healthy state. 



2. Some forms of greenness (e. g., the 

 leucocytosis) are certainly associated with 

 the presence of a greatly-increased amount 

 of copper in the oj'ster, while other forms 

 of greenness (e. g., the Marennes) have no 

 connection with copper, but depend upon 

 the presence of a special pigment Marennin, 

 which may contain a certain amount of 

 iron. 



3. We see no reason to think that the 

 iron in the latter case is taken in through 

 the surface epithelium of the gills and 

 palps ; but regard it, like the rest of the 

 iron in the body, as a product of ordinary 

 digestion and absorption in the alimentary 

 canal and liver. 



4. We do not find that there is any ex- 

 cessive amount of iron in the green Marennes 

 oyster compared with the colorless oyster ; 

 nor do the green parts (gills, palps, etc.) 

 of the Marennes oyster contain either abso- 

 lutely or relatively to the colorless parts 

 (mantle, etc.) more iron than colorless 

 oysters. We, therefore, conclude that there 

 is no connection between the green color 

 of the Huitres de Marennes and the iron 

 they may contain. 



5. On the other hand, we do find by 

 quantitative analysis that there is more 



