( 35 ) 
XL— ON THE CONNECTION BETWEEN OYSTERS AND 
INFECTION. 
From the earliest times more or less well grounded suspicion has been cast from 
time to time upon shellfish — chiefly Oysters and Mussels — as being the cause of out- 
breaks of disease amongst consumers, such as : — ist. Cases of sudden poisoning due to 
the presence of putrefactive products in the shellfish ; and 2nd. Diseases due to a specific 
micro-organism, where there is a period of incubation, and where therefore a consider- 
able interval has elapsed between the infection and the actual illness. In the latter case 
it is obviously much more difficult to determine with certainty the source from which the 
disease germ has entered the body ; and although many positive assertions have appeared 
of late years attributing outbreaks of enteric or typhoid fever to the consumption of 
oysters, still it must be pointed out that the connection between the two, although quite 
likely, has not yet been scientifically proved, and is only at present more or less of 
a possibility, or, at most, probability. 
During the past three years we have been making a number of observations and 
experiments, both in our Liverpool laboratories and at the Port Erin Biological Station, 
upon the conditions under which oysters live healthily, and upon the possibility, or even in 
some cases the probability, of their being the carriers of disease germs. During that period 
much public interest and apprehension has been raised by several recent outbreaks of 
typhoid popularly attributed to oysters, such as that of the Stirling Ball in October, 1895 ; 
that of the Wesleyan University in Connecticut, investigated by Professor H. VV. Conn in 
1894; and that in the south of France attributed to Cette oysters, reported upon by 
Dr. Chantemesse in 1896. It was obvious from these, and from numerous other outbreaks 
of typhoid attributed to eating oysters, that the conditions under which the shellfish were 
liable to become contaminated with sewage, and so be the carriers of pathogenic 
organisms, required investigation. The following is a brief account of our experiments 
and observations. 
A. The objects we had in view in entering on the investigation were as follows : — 
r. To determine the conditions of life and health and growth of the oyster by 
keeping samples in sea-waters of different composition ; e.g., it is a matter of discussion 
amongst practical ostreiculturists as to what specific gravity or salinity of water, and what 
amount of lime, are best for the due proportionate growth of both shell and body. 
2. To determine the effect of feeding oysters on various substances — both natural 
food, such as diatoms, and artificial food, such as oatmeal. Here, again, there is a want of 
agreement at present as to the benefit or otherwise of feeding oysters in captivity. 
