are undoubtedly one of the great causes of these differences. When a muscle is exposed to an open fire, as in the roasting of meat, the albumen is condensed, the gelatine melts, the fibrin filled with juices softens, the extractive matter flows in part with the gelatine and the salts held in solution; it is this that forms the gravy, which is, as we know, very different from melted fat. The exterior of the meat remains more dense than the interior; it is coloured by the extractive substance. The interior loses in part its natural colour; its consistence, its taste and its composition even change entirely. The fibres, as in ebullition, lose the power of contracting and of crisping from the action of strong stimuli and especially that of fire. No part in the animal economy is more easily altered by the digestive juices than the muscles. Almost all stomachs can bear boiled meat, whilst many reject other organs when cooked. Carnivorous animals seize upon the muscles of their prey in preference to the pectoral and gastric viscera. Muscular flesh is with most people the most common aliment, that with which they are never disgusted; it appears to be the most nourishing of all those, which are afforded by the different textures of animals; is it, as it has been said, because it contains the most azote? Whatever may be the reason, the general part which the muscular system takes in the digestion of all carnivorous animals, of man especially, is remarkable. Yet all the parts of this system do not appear to be equally agreeable to the taste of animals. It is, for example, a singular fact, that those bodies which are brought to our dissecting rooms, and which have been attacked by rats, are found almost always exclusively gnawed in the muscles of the face.