THE POLLUTION OF THE SEA 31 



siderable margin of error. The fact is that the identification 

 of the typical human Bacillus coli communis of Esherich is a 

 tedious and laborious undertaking applicable with difficulty in 

 public health laboratories where large numbers of analyses are 

 made. Often the search for this organism in shellfish or sea 

 water samples gives negative results ; and the not unnatural 

 tendency is for such methods to be employed as will give always 

 some positive results. The question now turns upon the degree 

 of certainty (as Mr. Balfour would say) to be attached to the 

 various reactions to be employed. One medical officer of health 

 says that glucose-fermenting organisms may be regarded as 

 being B. coli or at least " coliform " or " atypical " members of 

 a group all of which have the same significance for the public 

 health administration. Others say that the suspected organisms 

 must, at the least, ferment lactose. A compromise has been 

 effected by others who employ all the common tests, that is the 

 fermentation of glucose, lactose, cane sugar and milk, and the 

 fluorescence of neutral-red, but who give to each of these tests 

 a numerical value, and then sum the figures so obtained so as 

 to get a measure of the degree of contamination. It is not 

 difficult to see the confusion of thought implied in this ex- 

 traordinary procedure. Either Bacillus coli communis is specific 

 to man, or it is not. If it is specific, and if there are organisms 

 living free in nature, or in the intestinal canals of animals other 

 than man, which resemble it, then the bacteriological analysis 

 must be thorough and conclusive. If it is not specific, the 

 method is obviously faulty. If B. coli inhabits the alimentary 

 canals of domestic animals, sea birds and fishes, the significance 

 of its presence in shellfish and sea water is conditional upon 

 the proof that enteric fever is, or is not, communicable from 

 man to these animals and vice versa, or at least that a patho- 

 genic organism may pass from man to these animals and persist 

 there, retaining all its pathogenicity. 



One is surprised to find how very little real, conclusive, 

 scientific investigation has been carried out along these lines. 

 As I have already indicated, the Sewage Commission, either 

 through its evidence or its special investigations, elicited little 

 that has been of service in the actual administration of the 

 public health with respect to the questions considered here. 

 Less has since been done by the public health laboratories, and 

 the most unfortunate thing is that the apparently very full 



