KEPOliT OF COMMISSIONER OF FISH AND FISHERIES. CXXVII 



The physical features of Humboklt Bay, (Jalifoniia, seem unfavorable 

 for oysters, the saliuity of the water being almost as great as in the 

 ocean, and the summer temperature being too low to warrant the free 

 development of eggs. Furthermore, startish and stingrays are reported 

 as destructive, and Professor Washburn found one starlisli with an 

 eastern oyster in its grasp. The plants were in only fair condition in 

 August, and but few sliowed spawn, thus coutrastiug strongly with 

 the Vaquiua Bay oysters. 



GREEN OYSTERS. 



During the season of 1897-98, the oysters in the lower Chesapeake 

 basin, notably at Lynnhaven Bay, Va., were affected with greeu gills, 

 which condition, by rendering the crop unmarketable for the time 

 being, was financially very serious to the oystermen. At Lynnhaven 

 the first indications of this affection were noticed in June, 1897. The 

 color at that time was quite faint, and had completely escaped the 

 notice of the oystermen, but it gradually grew in intensity, until by 

 the first of September it had become extremely ijronounced. At the 

 opening of the season (in September) a few oysters were shipped, but 

 the greenness proved so repugnant to tlie consumers that the demand 

 soon entirely ceased, and practically no oysters were shipped from 

 Lynnhaven during the remainder of the season. 



The Commission received a large number of inquiries from boards of 

 health, boards of trade, oyster-dealers, and oyster-fishermen regarding 

 the wliolesomeness of green oysters. It is the popular opinion tliat 

 green-gilled oysters owe their viridity to the presence of copper, and are 

 therefore unwholesome; and this view has been recently strengthened by 

 newspaper references to a paper by two eminent English investigators. 

 Prof. Kupert Boyce and Dr. W'. A. Herdman, in which they record the 

 discovery of copper in unusual quantities in certain green American 

 oysters in England. Stinnilated by this discovery, a reexamination of 

 the question was begun by Dr. H. F. Moore, but has not yet been com- 

 pleted, owing to the intervention of other duties. Enough has been 

 accomplished, liowever, to show conclusively that the green color of 

 the oysters at Lynnhaven was not produced by copper. All of the 

 customary tests were applied without securing a copper reaction, and 

 specimens of the green oysters were submitted for quantitative tests to 

 Prof. J. D. Hird, of the Medical Department of Georgetown Univer- 

 sity, who found mere traces of copper, and reported that "the green 

 color was due to a hydrated ferrous compound." The exact source of 

 the green color has not been satisfactorily determined, but in no case 

 is it injurious. 



All attempts to obtain the pigment in solution have failed, and, like 

 "marennin," as Lankester has named the substance which produces 

 the characteristic green color of the oysters of Marennes, it is insoluble 

 in alcohol, ether, benzole, benzine, glycerin, water, dilute alkalies, and 

 dilute acids. 



