86o 



THE POPULAR SCIENCE MONTHLY. 



Report, will reach all the inhabitants of at 

 least one commonwealth. " Many amphib- 

 ians and reptiles," he says, "arc 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 con- 

 strict, 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 rep- 

 tile 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 0. P. Hay as a prob- 

 lem whose solution has not yet been effect- 

 ed. One of the difficulties in the way of 

 comprehending it originates in the fact that 

 all our analogies are derived from the obser- 

 vation of modern glaciers in motion down 

 steep inclines, while we do not fully recol- 

 lect that the great glacier in question most 

 probably came to a standstill in level terri- 

 tory. Bearing this point in view, the au- 

 thor concludes that a glacial ice-sheet mov- 

 ing over a nearly level surface would pos- 

 sess far less power of abrading its bed than 

 the same glacier would have while descend- 

 ing a slope of high angle ; through sub- 

 sidence 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 gla- 

 cier, and, finally, when they formed a suffi- 

 ciently 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 de- 

 tritus 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 Constitaents of Food. — In con- 

 sidering the different food-stuffs, 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, ac- 

 cording to other estimates — of the entire 

 weight. We must regard it as an essential 

 condition for the manifestation of all total 

 l)henomena. Certain solid inorganic ele- 

 ments 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 es- 

 sential 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 pres- 

 ent 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 wa- 

 ter properly aerated. Examined more close- 

 ly 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 under- 



