94 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



such information to the public health authorities with respect 



to any particular case of pollution. And there is no immediate 



prospect of this defect of administration being remedied, as 



it seems to be impracticable to get the requisite investigations 



made. 



The real easiness of purifying mussels. 



It is remarkable how very easily polluted mussels may 

 be purified from infected sewage- organisms in experimental 

 conditions. The experience of the Board of Agriculture and 

 Fisheries at Conway shows this very clearly. It has become 

 apparent to us several times. In May and June of 1916 I was 

 able to obtain a reduction of nearly one half of the sewage 

 organisms contained in mussels, merely by draining off the 

 water contained in the shell cavities. With a rapid circulation 

 of clean sea- water, even a few hours will cleanse a mussel to 

 all the extent that is necessary. 



In my experience mussels received by post for the purposes 

 of analysis are usually cleaner than mussels from the same spot 

 which are examined immediately after collection, and this is 

 simply due to the draining away of water from the shell cavities 

 into the vessel containing the shell-fish. In really accurate 

 work the vessel containing the sample ought to be sterilised, 

 and all the mussels in it, as well as the washings from the 

 vessel, ought to be cultivated. 



This easiness of cleansing sewage-polluted mussels is, 

 no doubt, satisfactory. But the real difficulties, with which 

 the scientific man has little to do, are the administrative ones. 

 It is of little use recommending and guaranteeing a process 

 of cleansing when one has, unfortunately, every reason to 

 believe that the administrative supervision will be defective 

 and inconsistent with the design of that process. 



The further difficulties, at present irremediable, it is 

 feared, are those of cost. In localities such as Conway, where 

 the industry is a large one, relatively expensive plant can 



