248 ELEMENTS OF WATER BACTERIOLOGY 



Valuable studies of the relation between shellfish 

 and disease have recently been published by Bulstrode 

 (1911) and Wilhelmi (1911) and Stiles (1912). 



Effect of Cookery upon Polluted Shellfish. It should 

 be noted that it is unfortunately not only raw shellfish 

 which are responsible for the spread of disease. Most 

 of the processes of cookery to which these foods are 

 subjected are insufficient to destroy pathogenic germs. 

 Clark (1906) found that clams and oysters in stews 

 and fried and scalloped in the usual manner were 

 generally free from colon bacilli and streptococci. 

 With steamed clams, however, the bacteria present 

 could not be destroyed except by a temperature high 

 enough and prolonged enough to ruin the clams for 

 eating. Rickards (1907) confirmed these results as 

 to the danger from steamed clams, while he found fried 

 clams and clams in chowder and scalloped oysters to 

 be practically sterilized. Oyster stew, however, is 

 not exposed to long continued heat as is clam chowder, 

 and fried oysters are less thoroughly heated than 

 fried clams in the ordinary processes in use. Oysters 

 in both of these forms and fancy roast oysters still 

 contained colon bacilli and streptococci. Buchan (1910) 

 finds that the ordinary methods of cooking mussels 

 do not remove the risk of typhoid infection. 



Bacteriological Examination of Shellfish. Without 

 further discussing the general sanitary aspects of the 

 subject it is important to consider just how one may 

 determine whether the oysters from a given region are 

 polluted or not. The methods which have been 

 developed for this work are essentially modifications 



