338 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



contain toxic quantities of Bacillus typhosus (producing 

 enteric fever), or possibly B. enteritidis (producing 

 Graertner poisoning). These organisms must, in any 

 circumstances, if they are present at all, always be present 

 in sewage in small numbers ; and when the latter is 

 intercepted in storage culverts and septic tanks, and then 

 turned into the sea and greatly diluted, the chance that a 

 mussel can be dangerously infected becomes very small. 



Most people will say that neither crude sewage, nor 

 a purified effluent, should find its way anywhere near a 

 shellfish bed. One must agree with this opinion, but it 

 is rather to be regarded as a " counsel of perfection." 

 When practicable methods of sanitary engineering and 

 sewage disposal are being considered, and when one 

 thinks of such a densely populated littoral as that of 

 Lancashire, it must be apparent that the ideal of 

 removing sewage so that it cannot approach mussel beds 

 is quite unattainable. 



The general conclusion, then, is that the mussels 

 from the skears and beds at Morecambe are not polluted 

 to such an extent as to constitute serious danger to the 

 health of those consuming them for food. In view of the 

 importance of the interests involved, I give below the 

 evidence on which this opinion is based. 



The Morecambe Sewage System, 



The accompanying chart shows the positions of the 

 mussel beds and the sewer outfalls. Altogether six sewers 

 empty into the Channel. No. I., which lies to the West 

 of the West End Pier, is the main sewer, and carries 

 seawards the treated effluent from the purification works. 

 It is a 24-inch iron pipe, and terminates near the skear 

 called " Seldom Seen," at the low water mark of spring 

 tides. No. II., the " Midland Culvert," is situated to 



