Page:Popular Science Monthly Volume 32.djvu/882

860 Report, will reach all the inhabitants of at least one commonwealth. "Many amphibians and reptiles," he says, "are of direct value to man. Many, as various kinds of turtles and frogs, are used as food, and such might even be profitably bred for that purpose. Many others are useful because of their propensity for devouring insects, mice, and rats, that are the pest of the farmers. A few, indeed, are dangerous; but it is worth any person's while to study our reptiles, if for no other reason than to be freed from constant fear of them. Of nearly a hundred species of amphibians and reptiles to be found within Indiana, not more than three or four are poisonous, and these are of rare occurrence. . . . Some others may strike, or bite a little, or constrict, as they have a right to do, but they are not venomous, and can do little hurt. Snakes that roll along like hoops, snakes that blow poison, snakes that sting with their tongues or the tips of their tails, and snakes that live for weeks in people's stomachs, are creatures of the imagination. Therefore, considering their usefulness as destroyers of vermin, no amphibian or reptile ought to be killed, unless it is to be employed for practical uses or preserved as a specimen for scientific purposes. . . . If the boys of the country are to be allowed to shoot all the birds and stone to death all the reptiles, we may yet be compelled to surrender to the vermin."

How the Glacial Drift was deposited.—The manner in which the glacial drift was deposited by the great ice-sheet has been studied by Professor O. P. Hay as a problem whose solution has not yet been effected. One of the difficulties in the way of comprehending it originates in the fact that all our analogies are derived from the observation of modern glaciers in motion down steep inclines, while we do not fully recollect that the great glacier in question most probably came to a standstill in level territory. Bearing this point in view, the author concludes that a glacial ice-sheet moving over a nearly level surface would possess far less power of abrading its bed than the same glacier would have while descending a slope of high angle; through subsidence of the glacial mass, caused by the earth's heat, and through other influences, a constantly increasing proportion of inert materials would collect in the lower layers of the moving ice; the accumulation of such materials would tend to retard the motion of the lower portions of the glacier, and, finally, when they formed a sufficiently great proportion of the mass, all motion of the lower portion would cease, and a permanent deposit would begin and continue to be made; other masses of detritus might be deposited at the foot of the glacial ice-sheet as a terminal moraine, and still other masses on the top of the already formed deposit when the glacier finally melted.

Mineral Constituents of Food.—In considering the different foodstuffs, says Dr. N. A. Randolph, we must regard water as of prime importance. In the average adult it constitutes from fifty-nine to sixty-five per cent—or even larger proportions, according to other estimates—of the entire weight. We must regard it as an essential condition for the manifestation of all total phenomena. Certain solid inorganic elements of food are also essential to the well-being of the organism, for in their absence the tissues can not be properly built up, nor can the processes in either the solids or the fluids of the body go on. The presence of mineral constituents appears absolutely essential to the integrity of proteid matter, and their withdrawal entails a loss of most of its distinguishing characteristics. A striking illustration of the necessity of this class of food-stuffs, and of the disturbances resulting from a very slight diminution in the amount of inorganic constituents present in the economy, may be found in the recent experiments of Ringer. Minnows, which thrived in brook-water, and remained alive in it without food for many days, died in a few hours when placed in distilled water properly aërated. Examined more closely in detail, the inorganic elements of food consist of the salts of the alkalies, salts of the alkaline earths, iron, silica, and fluorine in various combinations. The importance to the economy of the carbonates of the alkalies, and therefore the importance of fresh vegetable food from which they are most readily elaborated, must not be