SEA-FISHERIES LABORATORY. 121 



experiment on a large scale, and the conduct of the operations 

 was undertaken by the Board of Agriculture and Fisheries. 

 The works at Conway, now in course of erection, will therefore 

 provide the proper means of investigating the practical details 

 of the process to be adopted. 



While the few experiments to which I refer above were 

 being made some other questions suggested themselves. In 

 spite of the close attention that is now apparently directed 

 in this country to public health problems, precise information 

 with regard to the pollution of shellfish is difficult to obtain. 

 One finds no agreement among public health bacteriologists 

 as to what ought to be meant by " Bacillus coli." There are 

 no generally recognised methods of analysis, and there is no 

 generally recognised " standard of permissible impurity." On 

 the one hand bacteriologists like Houston, Klein, Savage and 

 others speak of " typical " and " atypical " Bacillus coli, 

 while on the other hand workers like MacConkey and Clemesha 

 have shown that faeces, sewage and polluted materials generally 

 contain a number of micro-organisms, all of which are what a 

 biologist would regard as " specifically distinct " from each 

 other. These micro-organisms are separable from each other 

 by the application of a number of fermentation tests, and a 

 careful analysis shows that the old " Bacillus coli " of Houston, 

 and others, is really a category of half a dozen to a dozen 

 distinct micro-organisms. If all these bacteria had the same 

 significance from the public health point of view, that is, if 

 they all indicate faecal pollution, there is no need of distinguish- 

 ing between them. Further, all these bacteria may live 

 normally and multiply in faeces, but it is not known whether 

 they live and multiply in estuarine sea-water, and in the 

 bodies of shellfish. Even if we did not know that many of 

 the micro-organisms which inhabit the human alimentary 

 canal die out when they pass into sea-water this would be 

 probable. One would expect that the profound change of 



