38 OYSTERS AND DISEASE. 



obtained from healthy subjects ; and that there was considerable toleration to peptonized 

 broth. 



V. The infection of the oyster by micro-organisms. 



The results of the bacteriological examination of the pallial cavity of the oyster, 

 and of the contents of the rectum, showed that in the case of those laid down in the 

 open water of the Bay the colonies present were especially small in number, whilst in 

 those laid down in proximity to the drain-pipe the number was enormous {e.g., 17,000, 

 in one typical culture, as against 10 in the former case). It was found that more 

 organisms were present in the pallial cavity than in the rectum. In the case of the 

 oysters grown in water infected with the Bacillus typhosus, it was found that there was 

 no apparent increase of the organisms, but that they could still be identified in cultures 

 taken from the water of the pallial cavity and rectum fourteen days after infection. 



It was found that the typhoid bacillus would not flourish in clean sea-water, and 

 our experiments seemed to show that it decreased in numbers in its passage along 

 the alimentary canal of the oyster. It would seem probable, therefore, that by methods 

 similar to those employed in the " Bassins de degorgement " of the French ostrei- 

 culturists, where the oysters are carefully subjected to a natural process of cleansing, 

 oysters previously contaminated with sewage could be freed of pathogenic organisms or 

 their products without spoiling the oyster for the market. 



It need scarcely be pointed out that if it becomes possible thus to cleanse 

 infected or suspected oysters by a simple mode of treatment which will render them 

 innocuous, a great boon will have been conferred upon both the oyster trade and the 

 oyster-consuming public. 



The remaining sections of this memoir deal with further points and investigations 

 in connection with the infection and disinfection of the oyster and other shellfish. 



