In all animals nutrition is performed by organic particles, which, separated from the gross mass of food by digestion, mingle with the blood, and assimilate with all parts of the body. But, independently of this principal effect arising from the quality, there is another which depends on the quantity of the food. The stomach and intestines of supple membranes, which occupy a considerable space in the body, and which, to preserve their tense state, and to counter-balance the force of the adjoining parts, require to be always in some filled measure. If for want of nourishment this space happens to be entirely empty, then the membranes, having no longer an inward support, bear down upon and adhere to each other, and these give rise to all the oppressions and weakness of extreme want. Food, therefore, as well as contributing to the nourishment of the body, serves as a kind of ballast to it. Its presence and quantity are equally necessary to preserve an equilibrium; and when a man dies for hunger, it is not more for want of nourishment than from not having a proper poise to the body. Thus animals, especially the most voracious, are so eager to fill up the vacancy within them, that they will swallow even earth and stones. Clay has been found in the stomach of a wolf; I have seen hogs eat it very greedily, and most birds swallow pebbles, &c. Nor is this from taste but necessity, for the most craving want is not to refresh the blood by a new chyle, but to maintain an equilibrium of the forces in the grand parts of the animal machine. THE WOLF.