IOWA ACADEMY OF SCIENCES. 
241 
which often culminate in prolonged illness, or even death; 
not only is waste of all kinds a menace to the public 
health, but it is also a repulsive sight to the aesthetic 
tastes of any civilized community. This last factor alone 
would make sewage disposal a question of considerable 
importance, as the value of property depends to a consid- 
erable extent upon its attractiveness, and anything which 
takes away from its good appearance deducts from its 
market value. 
The question of sewage disposal is coming to be recog- 
nized by the officers of the state boards of health in the 
various states. Perhaps, as leaders in this movement, may 
be mentioned Massachusetts, Connecticut and Maryland. 
The State Board of Health of Iowa (14), in its annual 
report for 1899, called especial attention to the almost utter 
lack of adequate means of sewage disposal in the small 
towns and cities of the state, and urges that some action 
be taken toward securing proper sewage disposal. 
In considering the question of sewage disposal it may be 
w r ell to define what is meant by sewage. Sewage, accord- 
ing to Barwise (8), comes from the Anglo-Saxon word 
seon, which means to flow down and includes the liquid 
contents of a sewer. Rafter and Baker (5), however, give 
sewage as including not only the combined water and 
waste matters flowing in sewers, but the mixed solids and 
liquid matter. This latter, it seems, is a better definition 
as it includes the solid excreta as well as the matter in 
solution. 
The kinds of sewage will necessarily vary with the im- 
posed conditions. The most common may well be termed 
domestic sewage, which contains kitchen slops and all the 
common refuse of ordinary dwellings. Factory sewage is 
more complex in most cases, depending, of course, upon 
the particular kind of factory under consideration. Pack- 
ing house sewage would hardly, come in this category, yet 
it plays a very important part in sewage disposal on ac- 
count of its peculiar constituents. Surface sewage, if such 
it may be called, is composed chiefly of water, and the 
washings from the streets, alleys, etc. City sewage being 
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