SEA- FISHERIES LABORATORY. 89 



that just the same shellfish were eaten by a number of people 

 without detriment, and this surely robs the original identification 

 of the shellfish with the cause of the disease of much of its 

 force. The proof cannot be regarded as satisfactory, and I 

 think the " attribution " of disease-conveying properties to 

 mussels, in some such case, ought to be challenged in the 

 Courts in order that some legal decision as to what constitutes 

 the proof should be obtained. 



The Validity of the Bacteriological Evidence. 



Nor can the results of a bacteriological analysis find legal 

 proof that the illness was the result of eating mussels that 

 contained typhoid bacilli, because when the illness is being 

 investigated its presumed material cause no longer exists. 

 It must be remembered that it is a very uncommon thing 

 indeed to find Bacillus typhosus in mussels taken from the 

 foreshore. I have found it myself, on one occasion, but even 

 then the identity of the organism was not beyond doubt.* 

 What the bacteriologist does look for, and usually find, is the 

 presence of what he calls Bacillus coli. This may be backed 

 up by finding that various other organisms of the same category, 

 Streptococci and B. enteritidis sporogenes, are also present. 

 The occurrence of these organisms is held to prove, and usually 

 does prove, that the shellfish in which they were contained 

 have been living in sea- water which contains sewage organisms 

 proceeding, via sewer outfalls and drains, from human dejecta. 

 None of these organisms, of themselves, convey enteric fever, 

 and all that is shown by the results of the analysis is that the 

 mussels were living in such conditions that they would have 

 taken up (and retained for a short time) typhoid bacilli had those 

 bacilli been present in the sea- water in which they were living. 

 The proof, from bacteriological analysis, is really this : had a 



* The biological characters were those of Ji. typhosus, bu1 the agglutina- 

 tion test was not ;i very stringent one and the lint her proofs were not 

 attempted. 



