186 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



find that Dr. Houston examined for the Commission over 

 one thousand oysters, from " some of the purest waters," 

 and from others " obviously liable to pollution," with the 

 result that nearly all the oysters, "from whatever laying 

 they were taken, contained Bacillus coli communis, or other 

 B. coli closely allied to it." Dr. Houston found, however, 

 a very much smaller number of these organisms in the 

 oysters stored in pure waters than in those from polluted 

 waters. Consequently the Commissioners state that they 

 should not be justified in recommending that the closing 

 of a bed or laying should depend as a matter of routine on 

 the results of a bacteriological examination — which is very 

 much the conclusion at which we had arrived, and the view 

 that I gave in my evidence. 



In taking samples of suspected shell-fish I would 

 attach great importance to personal supervision by a 

 scientific or fisheries expert. The samples should obviously 

 not be taken by the parties interested, and they should not 

 be taken by disinterested, but untrained collectors who 

 may miss seeing some qualifying factor or some important 

 piece of evidence. A knowledge of the local conditions, of 

 the influence of tidal and other currents, and of prevalent 

 winds, may be of great value in judging of the presence and 

 extent of pollution, and of the parts liable to be affected at 

 a particular time of clay or month. Consequently a 

 personal examination of the locality by a scientific man 

 is always important. Samples from various parts of the 

 same bed may have to be taken at different states of the 

 tide, and these should be chosen with knowledge and 

 discrimination. 



Any additional evidence that can be obtained from an 

 inspection of the physical and biological conditions on 

 the bed is all the more important because of our want of 

 exact knowledge as to the meaning and value of some 



