336 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



Medical Officer of the Borough. At this time the men 

 were working on the outer Heysham Skears and we there- 

 fore visited the latter at 5 a.m., the time of low water on 

 the morning tide. Further samples were taken from 

 " Grreat-Out " and " Little-Out " Skears, and from Ring- 

 Hole. Samples of sea-water were also taken from off 

 Great-out Skear, from off Baiting-Knot, from over the 

 main sewer outfall (at that time covered), and from Ring- 

 Hole. On this visit we also saw the main sewage culverts 

 and the purification works. 



Bacteriological analyses of the shellfish so collected 

 were made in the usual manner. The results show that 

 Bacillus coli was present in practically all the mussels 

 examined. But in no case was the degree of contamina- 

 tion considerable. There was a noticeable difference in 

 the results obtained from this analysis and those from the 

 analysis of July 19th. In this latter case the mussels 

 (which we did not personally collect) were apparently not 

 a representative sample from the Morecambe mussel beds, 

 although they may have been taken from a place from 

 which mussels are sent to the markets. 



To describe a mussel as dangerously polluted merely 

 because it contains Bacillus coli would be quite unjustifi- 

 able. This microbe is not, in such circumstances, 

 so far as we know, dangerous to health. Its presence in 

 a shellfish merely indicates that the latter is living in sea- 

 water which is exposed to some degree of sewage contamina- 

 tion. Its presence always indicates the 'possibility that 

 the shellfish in which it is found may, under certain 

 circumstances, come to harbour microbes of a nature 

 strictly pathogenic, such as the typhoid bacillus. But 

 when tjie number of B. coli in a mussel is few then this 

 possibility is remote. When the number is large, or when 

 the pollution is notorious (as in such cases as those of the 



