The visceral apparatus of Man presents very few characteristic peculiarities, by which it can be distinguished from that of the higher Quadrumana ; among the most re markable is the absence of the laryngeal pouches, which exist even in the chimpanzee and orang-outan, as dilatations of the laryngeal ventricles. Of the anatomy of the last-named animals in their adult condition, however, we know as vet too little, to enable its resem blance to that of man to be confidently pro nounced upon.
The conformation of the brain 'of Man does not differ so much from that of the chimpanzee and orang, as the superiority of his mental endowments might have led us to anticipate. The following are the principal differences which it seems to present : — 1. The mass of the entire brain is considerably larger in proportion to that of the body, and in proportion also to the diameter of the nerves which are connected with it. 2. In the external configuration of the cerebrum, we notice that the posterior lobes are more developed, so as to project further beyond the cerebellum than they do in any of the quadrumana ; the convolutions are more nu merous, and the sulci are deeper. 3. On ex amining the internal structure, it is found that the peripheral layer of grey matter is thicker, the corpus callosum extends further backwards, and the posterior cornua of the lateral ventricles are relatively longer and larger than they are in any Quadrumana. 4. The cerebellum, also, is proportionally larger. — The great size of the cranial portion of the skull in Man, as compared with the facial, produces a marked difference between his facial angle, and that of even the highest Quadrumana. According to Camper, who first applied this method of measurement, the facial angle of the average of European skulls is SO°, whilst in the ideal heads of the Grecian gods it is increased to on the other hand, in the skull of a Kalmuck he found it to be 75°, and in that of a Negro only 70° ; and applying the same system of measure ment to the skulls of Apes, he found them to range from 64° to 60°. But these last mea surements were all taken from young skulls, in which the forward extension of the jaws, which takes place on the second dentition, had not yet occurred. In the adult Chim panzee, as we learn from the measurements of Prof. Owen, the facial angle is no more than 35°, and in the adult Orang only 30°; so that instead of the Negro being nearer to the Ape than to the European, as Camper's estimate would make him, the interval be tween the most degraded human races and the most elevated Quadrumana is vastly greater than between the highest and lowest forms of humanity. It must be borne in mind that the facial angle is so much affected by the degree of prominence of the jaws, that it can never afford any certain information con cerning the elevation of the forehead and the capacity of the cranium ; all that it can in any degree serve to indicate, is the relative proportion between the facial and cranial parts of the skull. The small size of the face
of Man, compared with that of the cranium, is an indication that in him the senses are sub ordinated to the intelligence. Accordingly we find that he is surpassed by many of the lower animals in acuteness of sensibility to light, sound, &c. ; but he stands preeminent in the power of comparing and judging of his sensations, and of drawing conclusions from them as to their objective sources. Moreover, although none of his senses are very acute in his natural state, they are all moderately so ; and they are capable of being wonderfully improved by practice, when cir cumstances strongly call for their exercise. This seems especially the case with the tactile sense (see article Toucu, p. 1177), of which man can make greater use than any other animal, in consequence of the entire freedom of his anterior extremities, although there are many which surpass him in their power of appreciating certain classes of tactile impres sions. So, again, Alan's nerve-muscular power is inferior to that of most other animals of his size ; the full grown Orang, for example, surpasses him both in strength and agility ; and the larger Chimpanzee, according to the statements of the negroes who have en countered it, is far more than a match for any single man, and is almost certain to destroy any human opponent when once within has grasp. The absence of any natural weapons of offence, and of direct means of defence, are remarkable characteristics of Man, and dis tinguish him not only from the lower Mam malia, but also from the most anthropoid Apes ; in which it is obvious (both from their habits and general organisation) that the enormous canines have no relation to a car nivorous regimen, but are instruments of war fare. On those animals to which nature has denied weapons of attack, she has bestowed the means either of passive defence, of con cealment, or of flight ; in each of which Man is deficient. Yet, by his superior reason, he has not only been enabled to resist the at tacks of other animals, but even to bring them into subjection to himself. His intellect can scarcely suggest the mechanism which his hands cannot frame ; and he has devised and constructed arms more powerful than those which any other creature wields, and defences so secure as to defy the assaults of all but his fellow men.