Page:Popular Science Monthly Volume 36.djvu/554

538 of humanity are concerned. And it is a grave fallacy, for on the strength of it hundreds of families are induced each year to locate on the plains with the expectation of farming successfully. Failure follows, of course, and their only hope is to sell out to trustful newcomers, and move where the natural conditions are favorable to agriculture and the prosperity of farm-homes.



HAT takes place in an animal deprived of food may be explained by recurrence to the comparison between the animal and the machine, which, though very old and commonplace, is still exact and almost inevitable. In the machine, the burning of carbon gives rise to heat and force; animals also, burning carbon, develop heat and force. The same is true of plants, for they likewise disengage heat and force; only the plant disengages very little, and the animal much of them. While the plant is stationary, fixed to the ground, the animal is forced to move to find food. We might, indeed, say that all its wonderfully complicated organism is in substance only an apparatus attached to the stomach. The lower animals are hardly anything else than a stomach adapted to motion; and the animal is improved as its means of seeking food everywhere and at a distance are perfected. The animal goes out in search of food because it feels a want hunger. Nature, in fact, distrusts the intelligence of her children, and for that reason has given to all living beings instincts and wants; and has armed them all, without exception, with the sensation of hunger, to provoke them to seek nourishment. Without this irresistible feeling no being could live.

The sensation of hunger is a painful feeling of uneasiness and weakness. It is a general feeling, but is localized apparently in the stomach. Many ancient authors regarded it as a local sensation. Some said that the gastric fluid became more acid and produced a burning feeling in the stomach; others, that a contraction of the stomach took place. But, although the sensation of hunger is related to the stomach, it is really general. While it is sometimes alleviated by swallowing earth and stones, such inert substances may deceive it, but do not appease it. It has, moreover, been experimentally determined that the feeling of hunger is not abolished after cutting the pneumogastric or sensitive nerve of the stomach.

So, in thirst we feel a dryness in the back part of the throat. The local sensation is deceptive, for thirst does not depend upon 