160 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



4. To determine whether oysters not infected with a 

 pathogenic organism, but grown under insanitary con- 

 ditions, have a deleterious effect when used as food by 

 animals. 



5. To determine the effect upon the oyster of infection 

 with typhoid, both naturally — i.e., by feeding with sewage 

 water containing typhoid infection, and artificially — i.e., 

 by feeding on a culture in broth of the typhoid organism. 



6. To determine the fate of the typhoid bacillus in the 

 oyster — whether it is confined to the alimentary canal, 

 and whether it increases in any special part or gives rise 

 to any diseased conditions ; how long it remains in the 

 alimentary canal ; whether it remains and grows in the 

 pallial cavity, on the surface of the mantle and branchial 

 folds ; and whether it produces any altered condition of 

 these parts that can be recognised by the eye on opening 

 the oyster. 



7. To determine whether an oyster can free its alimen- 

 tary canal and pallial cavity from the typhoid organism 

 when placed in a stream of clean sea water ; and, if so, 

 how long would be required, under average conditions, 

 to render infected oysters practically harmless. 



B. The methods which we employed in attaining these 

 objects were as follows : — 



I. Observations upon oysters laid down in the sea, 

 at Port Erin — 



(a) Sunk in 5 fathoms in the bay, in pure water. 



(b) Deposited in shore pool, but in clean water. 



(c) Laid down in three different spots in more or less 

 close proximity to the main drain pipe, opening into the 

 sea below low-water mark. 



These observations were to ascertain differences of 

 fattening, condition, mortality, and the acquisition of 

 deleterious properties as the result of sewage contamination. 



