90 ILLINOIS ACADEMY OF SCIENCE 
could be more cheaply and readily obtained from rivers than 
from the ground by means of wells or springs, or from care- 
fully guarded watersheds, and as the health danger was little 
appreciated, river water was generally used. 
The first effort at treating a water for purification purposes 
was made in London in about 1830, when some sand filters 
were installed which were not very different in design from 
some of our modern plants. The object of these filters, how- 
ever, was primarily to remove the visible turbidity, and little 
thought was given to the possibility of removing disease germs. 
However, it was a matter of observation that the filtration of 
the water improved the public health and this gave an impetus 
to the further use of purification works. In the 70’s, following 
the clear enunciation of the germ theory of disease by Pasteur, 
there developed an appreciation of why filters produced an im- 
provement in health conditions, and methods were developed, 
principally by Frankland, for examining the bacterial efficiency 
of water purification works. 
Even so, progress lagged discouragingly behind knowledge 
and it required the frightful epidemic of Asiatic cholera in 
Hamburg in 1892 to thoroughly awaken the world to the dan- 
gers of impure public water supplies, and to give an object les- 
son in the difference between filtered and unfiltered water. 
The epidemic at Hamburg is an oft-repeated story, and while 
the lesson of the epidemic has been retold by many other epi- 
demics, yet the magnitude, the dramatic character, and its in- 
fluence upon water works practice and public health activity, 
renders it pardonable to again repeat the main facts. 
Hamburg adjoins Altona. Hamburg obtained at that time 
its water supply from the Elbe River, and delivered it to the 
consumers without purification. Altona also obtained its water 
supply from the Elbe River, but the water was passed through 
slow sand filters before being delivered to the consumers. In 
some way the river water became heavily infected with the 
organisms of Asiatic cholera. An epidemic broke out in Ham- 
burg involving within a period of two months 16,800 cases, 
and 8,600 deaths. In Altona there were approximately 500 
cases and 300 deaths, most of which gave a history of having 
used water in Hamburg. Asa bit of confirmatory evidence of 
the effect of the public water supply, there was a block of 
