242 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



BACTEBIOLOGICAL INVESTIGATIONS IN 



RELATION TO SHELLFISH POLLUTION 



BY SEWAGE MATTER. 



By J as. Johnstone. 



I. METHODS. 



II. THE MUSSEL BEDS IN THE MEESEY ESTUARY 



III. MUSSEL BEDS IN THE LUNE ESTUARY. 



IV. DEEP-SEA OYSTERS. 



I. Methods. 



It is advisable to give some account of the methods 

 employed in the analyses of the shellfish dealt with, since 

 doubt is often felt as to the identification of bacterial 

 species when statements of the methods employed are not 

 made. In the following investigations the method in 

 use in the Thompson- Yates laboratories at the University 

 of Liverpool, for the isolation and identification of 

 organisms belonging to the colon and typhoid groups, has 

 been employed. This method was elaborated by Dr. A. 

 McConkey,* and subsequently by Dr. A. Grunbaum,t and 

 depends on the inhibitory action of taurocholate of soda 

 prepared from ox-bile, on incubation at the relatively 

 ligh temperature of 42° C, and on the further identifica- 

 tion of the microbes thus isolated by their reactions with 

 various sugar and glycerine media. It is somewhat 

 laborious but it insists on a more stringent proof of the 

 identity of Bacillus coli, and other organisms derived 

 from the human intestine, than the other methods 

 commonly followed in the past. 



Batches of six to twelve mussels (or oysters) have 



* Reports. Thompson -Yates Laboratories, Liverpool, Vol. 4, pt. 1. 

 1 British Medical Journal, June 14, 100-2. 



