122 
EIGHTH REPORT. 
PURIFICATION OF MUNICIPAL WATER SUPPLIES. 
G. S. WILLIAMS. 
Mr. Chairman and Gentlemen : The subject of water purification 
here in America is a comparatively modern question. A few years ago, 
within our easy recollection, there were not many places where water 
purification was necessary, but with the growth of population the pos¬ 
sibilities of obtaining a satisfactory supply of water from the surface 
of the earth became materially decreased, and we have had to resort 
to those methods which have been in vogue in the old world for nearly 
three-fourths of a century. It is only within recent years that the 
ground water supply of Paris, for instance, has been discovered to be 
seriously polluted. For many years Paris boasted of a pure spring 
supply which was thought beyond all possibility of being contaminated, 
and yet for a number of years we have noticed that Paris has had a 
higher death rate from typhoid fever than other European cities. The 
springs furnishing water come from a fissured rock, and the drainage 
which contributes to these springs has become polluted, and in time 
it has been possible for that pollution to seep through the crevices of 
the rock and infect the springs, and the authorities have now dis¬ 
continued the use of several of these, and have substituted in their 
place filtered river water. They have further recently investigated 
American methods of water purification with a view of their applica¬ 
tion to the water of the river Seine. The record of water borne diseases 
is the best criterion of the water supply of a community, so far as the 
past is concerned, but from many sad experiences we are quite safe in 
saying that in these days no surface water supply is a safe supply. 
The distance to which pollution may be transmitted is dependent upon 
the life of the organisms which may produce infection. That life in 
the case of the typhoid germ is ordinarily ten days, and with occasional 
ones very much longer, perhaps as much as sixty days, perhaps 100, 
in fact we do not know how long they may live. Therefore the distance 
to which they may be transmitted is dependent upon their life, and 
their vitality at the time they may arrive in the conditions where they 
cause infection. It seems to me that it was pretty clearly shown that 
the water supply of St. Louis was being polluted by Chicago sewage 
after the opening of the drainage canal, for the death rate of typhoid 
fever increased immediately. The Supreme Court has seen fit to differ 
from me on that point, and perhaps I am not warranted in saying 
that this was the fact, but as the result of the investigation which was 
made, I not having, like the Court, to restrict my findings to the laws 
of evidence, feel quite thoroughly convinced that a very large portion 
of the increase of typhoid fever in St. Louis has been due to the 
discharge by Chicago of sewage into the drainage canal. 
Now as to the means of purifying water. The best, of course, is 
