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272
THE POPULAR SCIENCE MONTHLY.

huge herds; and it is more agile and infinitely more wary than its prairie cousin. The formation of this race is due solely to the extremely severe process of natural selection that has been going on among the buffalo-herds for the last sixty or seventy years." Elk were formerly plentiful all over the plains, but they have been driven off the ground nearly as completely as the buffalo. They are still, however, very common in the dense woods that cover the Rocky Mountains and the other great Western chains; but they are unfortunately one of the animals seemingly doomed to total destruction at no distant date. Already their range has shrunk to far less than one half its former size. "Ranged in the order of the difficulty with which they are approached and slain," says Mr. Roosevelt, "plains game stand as follows: big-horn, antelope, white-tail, black-tail, elk, and buffalo. But, as regards the amount of manly sport furnished by the chase of each, the white-tail should stand at the bottom of the list, and the elk and black-tail abreast of the antelope. Other things being equal, the length of an animal's stay in the land, when the arch foe of all lower forms of animal life has made his appearance therein, depends upon the difficulty with which he is hunted and slain. But other influences have to be taken into account. The big-horn is shy and retiring; very few, compared to the whole number, will be killed; and yet the others vanish completely. Apparently they will not remain where they are hunted and disturbed. With antelope and white-tail this does not hold; they will cling to a place far more tenaciously, even if often harassed. The former, being the more conspicuous and living in such open ground, is apt to be more persecuted; while the whitetail, longer than any other animal, keeps its place in the land in spite of the swinish game-butchers. . . . All game animals rely upon eyes, ears, and nose to warn them of the approach of danger; but the amount of reliance placed on each sense varies greatly in different species."

The Influence of Sewerage and Water-Supply on the Death-rate in Cities. By Erwin F. Smith. Pp. 84.

This paper was read at the Sanitary Convention at Ypsilanti, Michigan, July, 1885, and is reprinted from a supplement to the "Annual Report of the Michigan State Board of Health for 1885." As the author himself states, no effort has been made to present anything new in this article, but he has rather sought to place, in a form suitable and convenient for study and comparison, facts and data otherwise not readily accessible. It will seem somewhat surprising at first sight that so much of the material used is from foreign sources; yet this could not be avoided, as the writer forcibly points out, for, although there is no lack of so-called statistics in our own country, yet reliable and therefore valuable mortuary data are obtainable from but few localities. While we can not, in our space, mention all the questions and matters touched upon in this pamphlet, we would call especial attention to the charts appended to it. An examination of them ought to be sufficient to convince the most skeptical as to the direct relation an improvement in the system of sewerage and the water-supply of a city holds to the decrease in the death-rate of its inhabitants from certain diseases.

In Chart I, which records the deaths from typhoid fever to each 10,000 inhabitants before, during, and since the introduction of sewerage and water-supply, Munich, in Germany, shows for the years 1851 to 1859 twenty-one deaths from this disease to each 10,000 inhabitants, while for the period from 1874 to 1884 the rate has fallen to six and three tenths per 10,000.

Another chart, designed to show the protective influence of sewerage and water-supply in the cholera epidemic of 1865-'66, is divided into two groups. The cities enumerated in Group I were abundantly supplied with good water, and in most cases were also well sewered; those in Group II were incompletely sewered, or entirely destitute of modern sewers, and very dirty; their water-supply was scant or open to infection.

In the first group, where we find, among other cities, New York and Brooklyn, the former shows 12·8 deaths per each 10,000 inhabitants, the latter 16·5.

Memphis, Tennessee, which is placed in the second group, shows 268 deaths from cholera per each 10,000 of its population. St. Louis has 173·0 as its record; while Chicago, which in this group makes the best