SEA-FISHERIES LABORATORY. 165 



oyster and the behaviour of Bacillus typhosus in sea-water 

 and in the body of the shell-fish, and although we found 

 that we were, on occasions, able to recover our 

 experimental bacilli up to the twenty-first day from 

 infected sea-water kept in the cold, still in most cases they 

 disappeared before that time. At any rate there appears 

 to be no multiplication either in the sea-water or in the 

 body of the shell-fish — on the contrary, we found, as 

 others* have done, that in clean sea-water the Bacillus 

 typhosus rapidly decreases in numbers. 



In further experiments where the infected oysters 

 were subjected to a running stream of clean sea-water, the 

 results were definite and uniform. There was in all cases 

 a great diminution or total disappearance of the typhoid 

 organism in from one to seven days. The stream of water 

 enables the mollusc to purify its gills and alimentary 

 canal, and so free itself from the results of sewage 

 pollution ; and we found that in the great majority of 

 cases most of the bacteria were in fact cleared out in the 

 course of the first three days. 



A considerable amount of attention was also given 

 in these reports to other diseased conditions of the oyster, 

 and to the presence of copper and iron in abnormal 

 quantities in the tissues of shell-fish from some localities. 



Some of the earlier Lancashire Sea-Fisheries 

 Laboratory Reports, from 1895 onwards, gave brief notes 

 of the work that we were doing on the bacteriology of the 

 oyster, covering much the same ground as the reports that 

 were made to the British Association ; and as a general 

 summary, in the Lancashire Report for 1903 I had an 

 article, entitled " Sewage and Shell Fish," which dis- 

 cussed the evidence that had been accumulated locally 



* Dc Giaxa has shown that even if pathogenic bacteria are able to 

 live for a time in sterilised sea-water they soon die off in the struggle 

 for existence with the bacteria of normal sea-water. 



