“Different in character, however, from much of the refuse of manufacturing establishments is the sewage coming from dwellings, or the sewage (in its more restricted sense of excremental matter from animal sources) which comes from our manufactories. In fact, this foul material, coming from establishments employing a large number of operators, is likely, in many cases, to have a more injurious effect upon the stream into which it is thrown than refuse from the manufacturing operations. There are, however, some branches of industry which discharge refuse material offensive and dangerous to health. Such material is discharged from tanneries, wool-pulling and hide-dressing establishments, slaughter-houses and rendering-houses. ‘Too much stress can not be laid upon the importance of preventing the discharge of such refuse.’”—(Prof. Nichols, in Fifth Annual Report of Massachusetts State Board of Health.)
“The discharge of gas works is known to kill fish and destroy lower forms of animal life, which are important agents in preserving the purity of fresh water.
“One would not assert that the drainage of a single house would contaminate the water of a large river like the Merrimack so as to make it unfit for domestic use, yet we must beware how we depreciate the effect of sewage matter, even in a large stream.”—(Prof. Nichols, in Fifth Annual Report of Massachusetts State Board of Health, 1875.)
“With small amount of sewage the chances are favorable for the action of atmospheric influences, and particles of undecomposed material-propagating disease are rendered proportionally small, owing to the great dilution.
“A minute quantity may do much harm, because it is now generally believed, that it may hold the specific thing that propagates specific diseases.
“Rice water evacuations, of a cholera patient, however much diluted, still remains in liquid, although chemical test fails to detect it.
“The carcass of a dead animal, thrown into a river or pond, and confined there, so as not to be borne off bodily, gradually wastes away, and, in a longer or shorter time, the main part of the carcass has disappeared. What has become of it? A part has been converted into gaseous products of decomposition, as the offensive odors observed during the decay will testify; but another portion has been carried off by the stream as soluble nitrogenous organic matter. This nitrogenous matter would be detected a short distance away, with greater or less ease, according to the volume of water present; but in a stream of large size, or in a lake at no very great distance from the source of contamination, it would be impossible to discover any offensive matter. There is a limit to the delicacy of our tests: there is a point beyond which, at the present, we are not able to go. At the present time, a chemical analysis alone is not sufficient to determine the desirability of a given water-supply.”—(Rivers Pollution Commission, 1874.)
“The action of a float, upon or near the surface of the water, is no indication of the movement, back and forth, of the sewage in suspension. Portions of fresh sewage, it is true, will float, but after maceration the sewage has a specific gravity of about 1.325, and will sink, in still water, or very slow currents, at the rate of one foot per minute; but in a current of 170 feet a minute, it will not sink, but remain in suspension.”—(J. W. Adams, C. E., Water Supply Commission of Philadelphia, 1874.)
“This evidence, taken in connection with our own investigations, appear to us, conclusively, to prove:
“1st. That there is, at certain times, in human excreta, some material capable of producing disease, of a very fatal character, in human subjects.