52 ECONOMIC ZOOLOGY 



the water they will adhere to the gills and other organs of the oyster 

 and may, if the oyster be eaten raw, thus enter the human system. 



Although denied by some, there have been numerous cases of 

 typhoid fever and other diseases that have been traced to contaminated 

 oysters. It is claimed by some oystermen that during the cold weather, 

 when oysters are most in demand, they are, in a sense, hibernating and 

 take no food so that they cannot be seriously contaminated with disease 

 germs. Whether or not, this be true it is obviously important to see that 

 no oysters be sold that are taken from beds that are contaminated by 



FIG. 34. A steam power oyster dredge. (After J. L. Kellogg, Shellfish Industries, 

 from a Report of the N. Y. Forest, Fish and Game Commission.') 



sewage; most, if not all, of the States possessing oyster grounds now have 

 laws that are supposed to prevent this danger. In some cases oysters 

 from contaminated beds may be made safe by transplanting them for a 

 certain length of time to pure water, until they are free from pathogenic 

 organisms. 



There are federal laws that regulate the interstate shipment of 

 oysters except in sanitary ways, either in the shell or in sealed tin 

 or glass vessels, surrounded by ice. A bivalve that has opened its 



