From this cursory examination of the animal world we may gather the important conclusion, that from the structure of an extremity we may obtain a complete insight into the entire organisation of an animal; and thus the paws furnished with sharp retractile claws of the lion indicate at once to a naturalist its strong teeth, its powerful jaws, and its muscular strength of limb; while from the cleft foot of the cow, the complicated structure of its stomach, the definite peculiarities of its jaws, and its vegetable diet, may with equal certainty be predicated. Thus, as Paley justly observes, “In the swan, the web foot, the spoon bill, the long neck, the thick down, the graminivorous stomach, have all a relation to one another, inasmuch as they all concur in one design, that of supplying the occasions of an aquatic fowl, floating upon the surface of shallow parts of water, and seeking its food at the bottom. Begin with any one of these peculiarities of structure, and observe how the rest follow it. The web foot qualifies the bird for swimming, the spoon bill enables it to graze. But how is an animal, floating upon the surface of pools of water, to gaze at the bottom except by the mediation of a long neck? And a long neck is accordingly given to it. Again, a warm-blooded animal, which was to pass its life upon water, required a defence against the coldness of that element. Such a defence is furnished to the swan in the muff in which its body is wrapped. But all this outward apparatus would have been in vain if the intestinal system had not been suited to the digestion of vegetable substances.”[5] And, again, of the mole: “The form of the feet fixes the character of the animal. They are so many shovels; they determine its action to that of rooting in the ground; and every thing about its body agrees with this destination. The cylindrical figure of the mole, as well as the compactness of its form, arising from the terseness of its limbs, proportionally lessens its labour; because, according to its bulk, it thereby requires the least possible quantity of earth to be removed for its progress. It has nearly the same structure of the face and jaws as a swine, and the same office for them. The nose is sharp, slender, tendinous, strong; with a pair of nerves going down to the end of it. The plush covering, which, by the smoothness, closeness, and polish of the short piles that compose it, rejects the adhesion of almost every species of earth, defends the animal from cold and wet, and from the impediment which it would experience by the mould sticking to its body. From soils of all kind the little pioneer comes forth bright and clean. Inhabiting dirt, it is of all animals the neatest.” CHAPTER IV.