exception of a few isolated instances in which since 1896 

 an improvement in oyster layings and oyster storage has 

 been effected, the general system obtaining in a good many 

 instances, viz., of exposing oysters to " be periodically bathed 

 in sewage more or less dilute," is still the same as it 

 was in 1895, that is to say, " conditions which may at any 

 time involve risk of the fouling of such shellfish with the 

 excreta of persons suffering from diseases of the type of 

 cholera and enteric fever." As a matter of fact, I have in 

 several instances discovered the B. typhosus in shellfish 

 coming from polluted sources. These are the instances : 



1. In a sample of oysters derived from Grimsby in 1895. 



2. In a sample of oysters brought over direct from 

 America, 1903. 



3. In a sample of mussels gathered from a polluted place 

 on the shore of Southend-on-Sea, 1904. 



4. In a sample of oysters gathered from a place in Lang- 

 stone Harbour, about 600 yards distance from the Portsmouth 

 sewer outfall, 1904. 



I shall have presently an opportunity of showing that the 

 identification of this microbe in such shellfish is a matter of 

 no small difficulty, owing to such shellfish always containing 

 a large amount, and in preponderance, of sewage microbes, 

 greatly impeding the identification. In order to detect 

 the B. typhosus in shellfish or other materials (water, milk) 

 exposed to sewage pollution, and therefore harbouring sewage 

 microbes, the former must be present in appreciable numbers, 

 and if found would a priori conclusively indicate that the 

 specific pollution (i.e., with typhoid excreta) must have been 

 considerable. Until the last few years such identification 

 was an almost hopeless task, but at present the task has been 

 facilitated to a considerable degree by the discovery by 

 Drigalski and Conradi of a culture medium, on which the 

 presence of the B. typhosus can be easier detected than by 

 the former methods. I say easier, although I should not omit 

 to add that also by this method its presence must be in fair 

 proportion. The first case in which the typhoid bacillus was 

 found in the* Grimsby oysters was described in the Eeport of 



