168 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



e.c. may be tolerated? Before answering such a question 

 we must have further investigations. There are still too 

 many of the points involved which are left in doubt. For 

 example, we cannot be certain that all samples yielding 

 10 B. coli per c.c. are equally dangerous. Even if we 

 assume (as we probably may safely do) that pure oceanic 

 sea-water is free from B. coli and allied organisms, and 

 that these are to be taken as an indication of some sewage 

 contamination, we do not know how remote in time the 

 pollution may have been and how comparatively harmless 

 from a pathogenic point of view it may have become. It 

 is possible, or even probable, that B. coli may be 

 distributed to considerable distances in the excreta of fish 

 and sea-birds, possibly with some modification. Then 

 again, the bacteriology of the shrimp's alimentary canal 

 requires examination, and we may add the fishes that feed 

 upon the shrimp. There are also other sewage feeding 

 invertebrates that may conceivably pass on some organisms 

 and not others, and may favour the distribution of B. coli 

 under circumstances that deprive its presence of any 

 special [pathogenic] significance. 



" I am not arguing against the value of bacteriology, 

 but against a possible abuse of the method, and in favour 

 of a much wider investigation in which the laboratory 

 work will in all cases be supplemented, guided and 

 inspired by the marine biologist's work in the field. The 

 case of each estuary, bed, or laying must be regarded as 

 a separate problem to be solved with a full knowledge of 

 all the local conditions." 



In 1905 Mr. Johnstone reported to our Scientific 

 Sub-Committee on the detailed examination of the Llan- 

 fairfechan mussel bed in the Menai Straits. He and Dr. 

 Jenkins personally collected samples for analysis and 

 studied carefully the topographical relations of the shell- 



