180 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



re-laying 1 . The change after 4 days was most definite. 

 In the mussels as laid down the average number of 

 colon-like bacteria on each of the culture plates was 

 about 200; while in the case of those that had been 

 transplanted for 4 days the number in the similar cultures 

 was about 40. In most cases the reduction showed a loss 

 of 93 per cent, in the 4 days. In some cases the reduction 

 amounted to a total disappearance of the " coli " 

 organisms. It is clear then from these experiments made, 

 not in the bacteriological laboratory, but in the open 

 under natural conditions, that a very considerable degree 

 of cleansing follows when badly polluted mussels are 

 re-laid in unpolluted water, and that a period of four 

 days is long enough for practical purposes. After the 

 fourth day little or no further cleansing takes place. 



The recommendation* was therefore made that 

 mussels taken from certain specified grounds which were 

 known to be badly polluted ought to be re-laid on the 

 Morfa beach for at least 4 days before being sent to 

 market. Compared with the capital value represented by 

 the Conway mussel ground, and with the increased sales 

 which would no doubt result from the confidence on the 

 part of the purchaser that the mussels were free from 

 danger, the initial and current expenses of this system 

 of re-laying at Morfa would be quite trifling. It is 

 surprising that the fishermen do not endeavour to make 

 their industry more lucrative by themselves putting 

 the recommendation into force. 



The Corporation of Conway made an attempt last 

 winter to compel the fishermen to reform the fishery. 



* The results of the experimental work were reported to our 

 Scientific Sub-Committee and were discussed in February, 1909, and 

 again the following November; but it was found that the Sea 

 Fisheries Committee had no power to establish such/ cleansing depots, 

 nor to make regulations enforcing their use if established. 



