SEA-FISHERIES LABORATORY. 439 



not, however, one which is pathogenic — at least it has 

 not even been attempted to be shown that it may convey 

 disease via sea-water and shell-fish; it is suspect because 

 it may come from the human intestine, and there it may 

 be accompanied by the pathogenic Bacillus typhosus. If 

 we find " coli-like " microbes in shell-fish, then we 

 condemn the latter because these microbes may indicate 

 the presence of B. coli, and the latter may, in its turn, 

 indicate the presence of B. typhosus. This indirect 

 connection should be clearly understood. 



But the true B. coli communis is not restricted to 

 the human intestine. It occurs also in the faecal matter 

 of horses, cattle, pigs, goats and geese (at least). It may 

 also occur in human sputum, in the water draining off 

 cultivated land, in rain water, in dust, even in such 

 substances as crushed oats. Its presence in shell-fish is 

 not therefore a proof that the latter are contaminated 

 with human faecal matter. But we may argue, indeed 

 the " epidemiologist " has argued, that B. coli is not less 

 to be condemned even if it does proceed from the intestine 

 of the domestic animals. Now the covert assumption 

 made in this argument is that enteric fever may attack 

 these animals, that disease-producing organisms may be 

 voided by them, and that these organisms may transmit 

 enteric disease to man ; for the only epidemic disease 

 which is to be considered when we speak about sewage- 

 contaminated shell-fish is enteric fever. These several 

 assumptions cannot be proved to have any basis of fact. 



Let us assume, however, that both "coli-like" 

 bacteria and the true B. coli have the significance that 

 the public health official attaches to them. We have 

 then to consider what is this organism, or category of 

 organisms. It is quite evident on reading the literature 

 relating to sewage contaminated shell-fish that there is 



