24*2 
IOWA ACADEMY OF SCIENCES. 
essentially a compound of all the above mentioned, with 
the addition of others not enumerated, make it very com- 
plex and hard to deal with, as the plan adopted must 
needs be one which takes into account all its peculiarities 
and treats it accordingly. 
After what has been written on the subject of the 
necessity of sewage disposal it seems almost needless to 
try to add anything new. Yet it may be of interest to 
make a brief review of the already published facts. That 
sewage is a source of contamination and disease has long 
been established, many cases of typhoid fever have been 
directly traced to the lack of proper sewage disposal or the 
contamination of drinking water with sewage. Barwise 
records an outbreak of typhoid fever at Wesleyan Univer- 
sity, Middletown, Conn., in which there is indisputable 
evidence that it was due to the eating of oysters which 
had been grown in water contaminated with sewage. He 
also reports an interesting case of sewage contamination 
of the water supply at Tees. 
Bacillus typhosus is not the only pathogenic germ found 
in sewage as numerous experiments have shown, that 
Bacillus anthracis , (1) (the Bacteridie du charbon, of the 
French) not only lives in water but that it maintains its 
vitality for some time is well know. The spirillum of 
Asiatic cholera has been known to retain its vitality in 
the domestic water supply of Berlin from 267 to 382 days. 
(15). The Bacillus coli-communis and Bacillus cloacece while 
strictly speaking are not pathogenic are always to be 
regarded with suspicion when they occur in water as they 
frequently do. (5). Many disease germs may live in 
sewage for a short time and be propagated there. Thus it 
can be readily seen that polluted water is a possible source 
for almost any bacteriological disease. 
It is a fact of common observation that sewage pollution 
of streams is detrimental to the fish it contains, and indeed 
cases are recorded where the entire fish life of a stream for 
a given distance has been destroyed by sewage pollution. 
A case of this kind happened in our own state a few years 
ago at Marshalltown. 
