560 SANITARY NOTES ON POTABLE WATER. 
vations has been the recent epidemic of enteric fever at 
Caterham and Redhill. In this instance, an ordinarily very 
pure water was contaminated exceptionally, not by typhoidal 
discharges, mixed, as usual, with a very large proportion of 
ordinary sewage matter, but by typhoidal discharges only. 
The virus of typhoid was therefore surrounded by a com¬ 
paratively unusually small proportion of fermentable matter. 
And what is the practical result ? An “ exceptionally mild 
character of the disease.” As we read in Dr. Thorne's report 
(p. 10), only 21 deaths, or 6 per cent, amongst 352 cases.* 
This should be compared with the virulence of the preceding 
epidemic to which we referred. In the Pelikan there was an 
unusual accumulation of putrescent matter, and out of 28 
cases of typhoid nearly 43 per cent, were fatal. 
Without entering into more evidence I may, I think, 
draw the inference from the preceding quotations that 
experience has led, almost without exception, to the con¬ 
clusion that the virulence of the contagion of cholera and 
typhoid, as also probably of other contagious diseases, is 
increased whenever surrounded with putrid matter. This 
would then also apply to specifically infected drinking water, 
which contains fermentable matter. Those who look upon 
fermentative processes as the original cause of the spreading 
are obviously led to assume a still closer connection. Should 
we accept the view that putrid matter increases the severity 
of the symptoms of contagia, we arrive, like Dr. Biermer, at a 
very important conclusion. Some suppose that the specific 
virus of typhoid and similar diseases multiplies only within 
the bowels of persons affected, lying dormant as soon as 
it left them. 
If this were correct, any influence of fermenting matter on 
the specific virus outside the human or animal body could 
hardly be satisfactorily explained, and we are therefore, 
indeed, almost compelled to deny any such influence, or to 
accept that multiplication takes place, or may take place, 
as well without as within the animal body. The fact which, 
amongst a number of other instances, was proved by the 
well-known epidemic at Lausen, in Switzerland, that a com¬ 
paratively trifling polution of water by typhoidal discharges 
may be instrumental in spreading the disease over a very 
large area, is certainly most readily understood if we accept 
that view. 
* Dr. Duncan states in the pamphlet we quoted before (p. C) that the 
average of deaths from typhoid in Great Britain is nearly 11 per cent, of 
those attacked, but in the Army Medical Report, vol. xix, p. 11, we read 
that it is 20*5 per cent. 
