174 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



this was a locality where the grave pollution of the 

 mussel beds is due to the direction of the tidal streams. 

 He says, " The topography of the coast, indeed, renders 

 it impossible that these shell-fish can escape direct 

 contamination." The actual pathogenic organism of 

 enteric fever, B. typhosus, was isolated from the mussels 

 examined from this bed. 



In the same year (see our Annual Report for 1906) 



Mr. Johnstone commenced an extensive investigation of 



the mussel beds at the " Ring-Hole," and elsewhere in 



the neighbourhood of Morecambe, a 'matter of great 



importance on account of the various interests involved — 



including the transplantation of ill-nourished, stunted 



mussels from other localities to this more favoured 



spot for active growth. The bacteriological results 



showed that Bacillus coli was present in practically 



all the mussels examined, but Mr. Johnstone urges 



that to describe a mussel as dangerously polluted 



merely because it contains Bacillus coli would be quite 



unjustifiable. Its presence only indicates the possibility 



that the shell-fish in which it is found may, under certain 



circumstances, harbour strictly pathogenic organisms such 



as the typhoid bacillus. When the number of Bacillus 



coli in a mussel is small, then this possibility is remote. 



When the number is very large, or when the pollution is 



notorious (as in such cases as those of the mussels at 



Egremont, Rock Ferry, or St. Annes), then we may 



reasonably conclude that the shell-fish should not be 



used for human food. We agree with the Sewage 



Commissioners when they say, " If it should be seriously 



contended that the mere presence of Bacillus coli or coli- 



like microbes in an oyster should condemn it, few oysters 



would probably escape condemnation." The same is no 



doubt true of mussels. 



