“Some may imagine, at a first glance, a closer resemblance between the human stomach and the lion’s than between the human and that of the sheep. But when they are viewed in relation to their proper food, their closer resemblance will vanish at once. It should be particularly observed that, so far as mere bulk is concerned, there is a greater similarity between the food of frugivorous animals and carnivorous animals than between frugivorous and herbivorous. The digestion and assimilation of coarse herbage, as grass, leaves, etc., requires a more complicated digestive apparatus than grains, roots, etc., and these more so than flesh and blood. The structure of the stomach, therefore, in such cases, seems precisely adapted to the food we assume Nature intended for it.”[8]
_The Liver._—Dr John Smith, in calling attention to the many distinctions between the bodily structure of man and that of the carnivora, pointed out the following differences among others:—
“In the carnivora and rodentia, which present the most complex form of liver among the mammalia, there are five distinct parts; a central or principal lobe, corresponding with the principal part of the liver in man; a right lateral lobe, with a lobular appendage, corresponding to the ‘lobulus Spigelii’ and the ‘lobus caudatus,’ and a small lobe or lobule on the left side. Through the whole animal series, however, the magnitude of the liver varies in inverse ratio to the lungs.
“In man, the liver is much less developed than the same organ in many other mammalia; and presents, as rudimentary indications, certain organs which are in other animals fully developed. Europeans, and the inhabitants of Northern climes, who partake more of animal food, have the liver much larger, and its secretions more copious, than the inhabitants of warm climates. Perhaps this, in some measure, depends upon the amount of non-azotised articles taken along with the flesh of animals, by which means the system is supplied with more carbon than is needed. So that the enlarged liver is attributable to gross living on mixed diet, rather than to an exclusively animal diet.”
“The temporal and masseter muscles, by which the motion of the lower jaw is effected, are of immense size in carnivorous animals. The temporal muscle occupies the whole side of the scull, and fills the space beneath the zygomatic arch, the span and spring of which are generally an index of the volume of this muscle; while the extent and strength of the arch indicate the development of the masseter muscle. On the contrary, the pterygoid muscles, which aid the lateral movement of the jaw, are extremely small. The zygoma is of great size and strength in the carnivora; consisting of a long process of the masseter bone, overlaid by the usual process of the temporal bone, which is equally strong. The arch extends not only backward but upward, by the bending down of the extremity; the line of anterior declination falling precisely on the centre of the carnassière tooth—the point in which the force of the jaws is concentrated, and where it is most required for cutting, tearing, and crushing their food. In ruminants, the zygomatic arch is short, and the temporal muscles are small; but the masseter muscle on each side extends beyond the arch, and is attached to the greater part of the side of the maxillary bone. The pterygoid fossa is ample, and its muscles are largely developed. The arch is small in man, the temporal muscles moderate, and the force of the jaws comparatively weak.”