SEA-FISHERIES LABORATORY. 91 



made in June, 1916, and/ these showed that the pollution of 

 the Estuary had notably increased. 



The pollution of Barrow Channel was also studied. In 1908 

 Mr. Scott and I sampled the water there throughout one day 

 at intervals of two hours. At about low water we found the 

 degree of pollution was about 200 to 1,000 sewage organisms 

 per cubic centimetre. 



In May and June, 1916, Mr. Scott sent me numerous 

 samples of water from the same place, and I found that all of 

 these were sterile (so far as sewage organisms were concerned) 

 in 1 c.c. But we suspected that sewage organisms contained 

 in sea-water undergo diminution when the water is kept long 

 before analysis, and further samples were therefore taken 

 and analysed within half an hour after collection. The mean 

 number of sewage organisms was about 6 per c.c. This remark- 

 able condition was observed at a time when the population 

 of Barrow-in-Furness was abnormally large — augmented by 

 the great influx of munition workers. Doubtless it is due to 

 local, military, sanitary administration. 



Other Inspections and Analyses. 



Some other cases of mussel pollution — at Heysham and 

 at West Kirby, in Cheshire — have also been examined. 



Methods of Analysis and Standards. 



As time goes on bacteriological examination of polluted 

 mussels becomes a matter of more and more difficulty, and 

 it would, perhaps, be advisable to lay little stress on the 

 results were it not that the general practice of local health 

 authorities compels us to have recourse to analyses. There is 

 still no recognised " standard of impurity," and one cannot 

 say that it is desirable that there should be such, for it is 

 highly probable that the establishment of a quasi-legal standard 

 of bacteriological impurity would only lead to administrative 

 absurdities and do no real good. 



