SEA-FISHERIES LABORATORY. 461 



from Morecambe Bay, out from Flookburgh — a place 

 that we can hardly imagine is polluted by sewage. 

 These Southport cockles may, then, be regarded as pure. 

 But the case was very different with cockles taken from 

 the sands near Ansdell. Here the bacterial contents 

 were about 2,000 sewage bacteria per cockle. These 

 results, moreover, correspond with the reputation of the 

 shellfish : no epidemiological evidence is forthcoming 

 with regard to the Southport cockles, whereas those 

 gathered near Ansdell and St. Anne's have been regarded 

 with strong suspicion as carriers of disease. 



This bacteriological impurity is to be associated with 

 the direction taken by the flow of the diluted sewage. 

 Not only does the contaminated ebb-tide water from the 

 upper part of the Kibble channel flow near to the cockle 

 beds between the old North Channel and the New Gut 

 Channel, but the influence of the sewer outfalls at 

 St. Anne's and Ansdell is apparent here. This recently- 

 discharged sewage is far more serious than that coming 

 down from Preston, or perhaps across from Southport. 

 It is, indeed, unlikely that much of the sewage from the 

 two last sources can reach the cockle beds on Salter's 

 Bank, for the ebb-stream sets out to sea through the main 

 channels, Pinfold, Old Gut and New Gut. On the other 

 hand, the fairly strong flood and ebb streams set parallel 

 to the land along the depression — that of the old North 

 Channel — which exists close inshore from St. Anne's 

 down to Fairhaven, and both streams must pick up the 

 sewage from St. Anne's and Ansdell and distribute it 

 along the edges of the banks. The contamination of 

 these cockles may therefore be not very remote, and of 

 course the degree of contamination in the close inshore 

 beds may be fairly considerable. 



The mussel beds are also exposed to very different 



