This machine is sometimes called the Artificial Mother, and it is worthy of notice that it is no modern invention, the ancient Egyptians having used it more than three thousand years ago.
With regard to Nature, it would have been simple enough to give one illustration of a bird sitting on her eggs, but I have preferred to select a different subject, as more relevant to the question of artificial heat.
There is an insect to which we have had several occasions of reference, namely, the Wurble-fly of the ox, scientifically known as Œstrus bovis.
The eggs of this insect are deposited in the skin of the ox, and are there hatched by the heat of the animal. In proportion as the larva grows, it raises lumps upon the skin, these being practically the roofs of the artificial home. There are several other species of the same genus, all of which have their eggs hatched by the heat of the animals on which they are placed. There are, for example, the common Bot-fly (Œstrus equi), whose eggs are hatched in the interior of the horse, and the Sheep-fly (Œstrus ovis), whose eggs are hatched in the head of the sheep. The common Snake leaves her eggs to be hatched in the artificial heat produced by decaying vegetable matter.
We now come to the preservation of provisions.
In the first place, we have the well-known “cache” of Northern America—i.e. a spot wherein provisions are hidden, and their locality only marked by signs intelligible to those for whose use they are intended. It is, perhaps, hardly necessary to mention that many creatures—such as the dog, the squirrel, and most of the crow tribe—are in the habit of concealing provisions for future use.
In those parts of the world, however, where the rights of hunters are acknowledged, any one who kills a deer, or other animal of chase, and is not able to carry off the entire body, can preserve it for his own use. He simply cuts it up in hunter fashion, and hangs the various portions to branches of trees, where they are out of the reach of wild beasts. Stores like these, such as are shown in the illustration, are always respected, and no hunter would dream of helping himself to the game which was killed and dressed by another.
Beasts of prey, however, cannot be expected to be so punctilious, and in consequence the hunters hang their meat to branches which cannot be reached.
In Nature we find many similar examples, one or two of which are given on the left hand of the illustration.