334 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



typhosus has been isolated from shellfish., though there is 

 little doubt that it is often present. The microbe is one 

 which possesses little vitality in sea water (Herdman and 

 Boyce), or in the alimentary canal of the mussel or oyster 

 (Klein), and its presence, therefore, indicates recent, and 

 therefore, dangerous pollution, a result which is indeed 

 apparent from the unusually large numbers of Bacillus 

 coli present in the mussels examined. 



A quantitative analysis of the bacteriology of the 

 mussels was also made (as regards B. coli) by the method 

 of decimal dilutions of Dr. A. C. Houston, Bacteriologist 

 to the Royal Commission on Sewage Disposal. Five 

 mussels were taken and removed from their shells with 

 sterile precautions. The liquid from the shell cavities 

 was made into an emulsion with the bodies of the shell- 

 fish and this emulsion was made up to the volume of 

 500 cc. with sterile water. 1 cc. of this liquid, therefore, 

 contained l/100th part of one mussel. The liquid was 

 then diluted so that 1 cc. contained 1/1,000 part of one 

 mussel and the process was repeated. In this way 

 emulsions were obtained which contained: — 



A. 1/100 part of a mussel. 



B. 1/1,000 part of a mussel. 



C. 1/10,000 part of a mussel. 



D. 1/100,000 part of a mussel. 



1 cc. of each was then inoculated on neutral red agar 

 as before, and also in milk under anaerobic conditions. 

 A contained about 20 colon-like organisms. 



r 9 



^ }) >} **> >j J? 



D was sterile. 

 One of the colonies in C was produced by B. coli. 

 This organism was, therefore, present in 1/10,000 part of 

 a mussel (average of five examined). 



