SEA-FISHERIES LABORATORY. 269 



and neither of these was B. coli in the strict sense. In the 

 former case there was independent evidence of the 

 dangerous condition of the shellfish, and the number 

 of colon microbes present was so great that we must 

 conclude that the degree of contamination greatly 

 exceeded any standard number of bacteria that might 

 reasonably be agreed upon. In the latter case any sewage 

 contamination to which the shellfish were subjected was 

 remote in point of time, and the number of colon bacteria 

 was so small that we must conclude the degree of con- 

 tamination was less than any reasonable standard of 

 impurity. But what is to be said of the condition of the 

 Wallasey mussels? Here from 3 to 21 colon-like 

 microbes were found iu x^th (roughly) of the stomach 

 contents of one fish, and of these about one-half were true 

 B. coli. Some doubt might be felt here as to whether or 

 not the degree of contamination was a dangerous one. 

 But in this case the pollution is remote ; the mussel bed 

 is, indeed, near a sewer outfall, but the liquids discharged 

 by the latter do not flow directly on to the bed> but are 

 probably widely distributed by the strong ebb tides 

 running in this locality. We know that the water of the 

 Mersey does contain B. coli, and it is probable that the 

 mussels are infected from this water, some of which 

 probably flows over the bed with every ebb tide. There 

 is no evidence of any disease being communicated by the 

 consumption as food of these shellfish, and, considering 

 that the pollution is remote, and that the actual numbers 

 of colon bacteria obtained from each fish are small, it is 

 to be concluded that the degree of contamination is not a 

 dangerous one. It must be remembered, too, that 

 probably most, or all, shellfish beds round such a thickly- 

 populated area as the English seaboard are polluted by 

 sewage to some extent. 



