36 Part III. — T'Lventy-sixth Annual Beport 



Although very little work has been done on this subject in this country, 

 the results of Houston and Eyre are interesting and invite comparison. 



Houston, experimenting on fish obtained off the Norfolk coast — a 

 locality remote from sewage pollution — found that only 13 per cent, of 

 the cases he examined exhibited typical bacillus coli, 52 per cent, atypical, 

 while 34 per cent, gave negative results. From these results he concludes 

 that, although fish in a sewage-free locality may sometimes contain 

 typical bacillus coli in their interior, it can hardly be the case that even 

 coli-like microbes are present naturally in abundance in fish. 



Eyre, working about the same time, and finding the coli bacillus almost 

 universally present in the intestinal canal of the lower mammals and 

 birds, obtained a large variety of fish off the Lincolnshire coast, and had 

 no difficulty in isolating typical bacillus coli from every fish experimented 

 with. 



It is thus quite reasonable to suppose that either a sewage-polluted or 

 a sewage-free environment will exercise some influence in determining 

 the extent to which bacillus coli or coli-like organisms may be present in 

 fish inhabiting such localities. I have examined several varieties of fish 

 caught in Aberdeen Bay, round the area where sewers discharge, and in 

 many of these the colonies of the coli bacillus were present in enormous 

 numbers in the media used ; whereas in the case of fish known to 

 be caught some distance from land the colonies were generally few in 

 number. 



Houston, working on guillemots and gulls, found that, whereas the 

 intestinal contents of the former, in culture, yielded negative results as 

 regards the bacillus coli, bacillus enteritidis sporogenes, and strepti-cocci, 

 the intestinal contents of the latter contained bacillus coli in enormous 

 numbers, and also, although not so numerous, bacillus enteritidis sporo- 

 genes and strepti-cocci — the intestinal organisms closely associated with 

 the coli hacillus. He ascribes this result to the different habits of 

 feeding ; guillemots are clean feeders, whereas gulls feed on all sorts of 

 filth. 



In this respect the study of the life history of the mussel is very 

 interesting and instructive, for its varying life conditions appear to have 

 a considerable influence in determining its wholeaomeness or unwhole- 

 someness. Some investigations were made by Virchow and Schmidtmann 

 and by Wolff and Kbnig. The former found that when poisonous 

 mussels were left in pure sea water they became harmless in less than one 

 month. The latter showed that if non-poisonous mussels were placed 

 near a sewage outlet, or even in the water of a harbour, they became 

 poisonous in about two weeks. If now these mussels are transferred into 

 the neighbourhood of a sluice, where the water is frequently changed, 

 they very soon again become harmless. 



These considerations raise some very important questions. It is 

 possible that the bacillus coli may not be a natural nor a necessary 

 inhabitant of the intestinal canal in certain lower animals, but may have 

 become so by finding a temporary lodgment through the exigencies of 

 living and feeding, and then by laying aside the saphrophytic and taking 

 on the parasitic habit; while, as already shown, the number of coli 

 present in a fish depends largely on topographical considerations 

 influencing the type of feeding. 



Such questions as these, and the now recognised possibility of birds, 

 fish, etc., as important bacillus coli carriers, infecting one another, 

 polluting oyster-beds, rivers, and streams, foodstuffs and water supplies ; 

 as also the different views held whether all kinds of excremental 

 pollution is potentially dangerous to health, or whether it is only danger- 



