242 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 sew^age. He 

 also reports an interesting case of sewage contamination 

 of the water supply at Tees. 



Bacillus typJiosHs is not the only pathogenic germ found 

 in sewage as numerous experiments have shown, that 

 Bacillus aidhyacis, (1) (the Bacteridie da charbon, of the 

 French) not only lives in w^ater 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 cloacea' 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. 



