134 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



watched and compared -with that of similar oysters left on 

 the bed at Bangor. 



I think it is a question whether the spat on the Ogwen 

 bed is derived wholly from the old oysters in sight, or 

 whether its source may not be individuals in deeper water 

 somewhere in the neighbourhood. I propose to visit the 

 bed myself during next spawning season in order to try 

 to settle this and several other questions in connection 

 with the reproduction and spatting of the oyster. 



The further point has been raised that the Ogwen River 

 oyster-bed may be liable to sewage contamination from 

 the drains of Bangor. The observations made by Mr. 

 Scott and the samples brought back by him, although not 

 absolutely conclusive on this point, certainly suggest 

 material of sewage origin, and it is difficult to believe that 

 under certain conditions of wind and tide the bed can 

 escape from pollution by the town drainage. However, 

 this is a matter that may require further investigation, 

 and in any case it does not affect the value of the locality 

 for the production of spat and the rearing of young 

 oysters -which may be fattened elsewhere before being 

 placed on the market. The whole question of the dis- 

 posal of sewage and the pollution of our rivers, estuaries 

 and sea shores is one that is in an unsatisfactory condi- 

 tion, and requires more careful consideration than it has 

 yet received. 



I desire to draw the attention of the Committee to some 

 points in connection with the so-called " Bacterial treat- 

 ment " of sewage (by coke filter beds or by septic tanks), 

 which is now being adopted in various parts of the 

 country. The recently published report to the London 

 County Council by Professor Clowes and Dr. Houston 

 shows that the effluent discharged after such treatment, 

 although it may seem pure and have some objectionable 



