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Passing thus over the groups of Radiata, Mollusca, and Articulata, we reach the subdivision of the animal kingdom termed Vertebrata, in which man is included. But before proceeding to the consideration of man's characteristics, the main topic of this paper, it may be here stated that, notwithstanding the occasional and unavoidable use of certain technical terms, our aim is rather at a popular than a scientific exposition of the subject. In the language of Fontenelle, in the preface to his "Pluralité des Mondes," "I have wished to treat philosophy in a manner not philosophical: I have endeavored to bring it to a point where it would be neither too dry for the taste of the world, nor too light for people of learning." Nothing has, in truth, tended more to prevent the progress of scientific knowledge among the reading public, than the unpopular manner in which scientific truths have been explained by those who pretend to teach philosophy. The general reader is not to be attracted by mathematical erudition or the statement of prolix propositions; but he may be allured to the study of natural phenomena, if presented by means of familiar illustrations and the simplest methods of demonstration. We are not, at the same time, ignorant of the fact that he who attempts to render popular a scientific subject, encounters the risk of being deemed superficial; for, as dulness and pedantry, by long-established prescriptive right, have guarded the portals of the temple of science, so it has become quite natural to regard a liberal endowment of dulness, in connection with a due proportion of technical precision, as unerring indications of a profundity of knowledge.

But the present age-the era of cheap literature-is regarded as one of general information-the enlightened age of the nineteenth century! As much, however, of this literature consists of low and vile French romances, it is doubtful whether their numberless readers have improved much in natural science. It was taught by the celebrated John Locke, in his "Elements of Natural Philosophy," that "all stones, metals, and minerals, are real vegetables; that is, grow organically from proper seeds, as well as plants." Now if the question-Do stones grow?— were asked in these days of cheap literature, it is by no means clear that the majority would give a correct answer.

Compared with the other divisions of the animal kingdom, the class of vertebrata is characterized by a great development of the nervous system. It is a general character of this group, that the development of all the other organs shall be subordinate

to that of the nervous system; and here we also find that the skeleton is always so arranged as to inclose and protect the nervous centres, while they give, on their exterior, attachment to the muscles by which the body is moved. Moreover, while the lower orders of animal creation seem to grow like plants, each part increasing by its own separate vitality, and evincing little dependence on any other, we observe in the vertebrata, in consequence of the predominance of the nervous system, all the different organs inseparably interwoven, and exerting the most close mutual dependence.

The vertebrata are again subdivided into the four classes of Fishes, Reptiles, Birds, and Mammalia; and this last class, to which man pertains, at least so far as his corporeal structure is concerned, is the most highly organized, standing at the head of the great scale of organic nature. In the mammalia, we find the brain in the highest state of development; and here also we discover, even when we exclude man, a most striking subordination of the instinctive powers to what may be termed reasoning faculties. So great is the sagacity of the dog, the elephant, or the monkey, that they display, under a great variety of circumstances, an intelligent adaptation of means to an end; and although these are educable in the highest degree next to man, yet the difference between man and these brutes, in this respect, is so strongly marked, that it has been proposed by some naturalists to exclude him not only from the group of mammalia, but from the whole animal kingdom. This, however, would be unphilosophical, inasmuch as the psychical phenomena of man, in his present state of being, we have no reason to believe are less closely connected with their material tenement, than in the brute creation. But it is wholly unnecessary thus to exclude man from the animal kingdom for fear of blending his nature with that of the brute creation; for it will be seen in the sequel, that, independent of his spiritual attributes, he possesses characteristics the most peculiar.

Characteristics of Man.-Between man and the rest of the animal kingdom, there is a broad line of separation. It is to man alone that the consciousness of the progress of time, of the decay of his strength and faculties, of the approach of death, and of the loss of friends, pertains; and he alone is endowed with the attributes of religion-the belief in a subjection to invisible powers and in accountableness to these unseen agents in a world to come. Although it is evident that man's reasoning

powers, as well as his affections, differ rather in degree than in kind, from those of the inferior animals; yet in brutes, the affections, as for instance the attachment to offspring, cease with the necessity for their existence. These feelings in the human breast, on the contrary, do not die, but become the very bonds by which society and all the endearing relations of life are maintained. But, in addition to these peculiar privileges, man is also distinguished zoologically by certain striking anatomical characters, which it may be well to review here somewhat in detail; and from this survey it will be found that man, the harp of a thousand strings," is unquestionably endowed with a perfection of structure best adapted for a being destined to exercise intelligent free-will.

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Man has a peculiar adaptation to the erect position; and it is this characteristic of the human skeleton, which contradistinguishes it from that of all other animals. This attitude may, in truth, be regarded as the symbol of a being, elevated by his spiritual endowments above the servile state of mere animal What classic scholar is there, who does not recollect the almost inspired words of the profane poet-os homini sublime dedit, etc.!

nature.

"Man alone," says Professor Green, the philosophic anatomist and accomplished writer, "is erect. It is to this posture that the body of man owes the character, impressed on the whole frame of its emancipation from subserviency to the mere animal needs, and becomes expressive of mind and of free and intelligent action. It will be seen that the lower limbs, answering the purposes of support and locomotion, have alone any obvious or necessitated utility; while the upper extremities are, in consequence, left at liberty, as the ready and facile instruments of his will. Hence, too, the senses are best freed from their servitude to the bodily wants, and the countenance is raised as the expressive exponent of thoughts and feelings, which the mouth. declares and interprets by words. And thus, as the stem bears the corolla, the head is carried on high as the most noble part of the frame which it surmounts; all the rest of the body seems as if intended to carry it; and when considered in its fitness for expression, it may be said to be the representative of the whole

man:

-"A creature, who, not prone

And brute as other creatures, but endued
With sanctity of reason, might erect

His stature, and upright, with front serene,
Govern the rest, sell-knowing.

But to illustrate this point anatomically. Thus the cranium, articulated with the top of the vertebral column, is so placed that a plumb-line dropped from the point of its support would fall through the centre of gravity between the feet. The foramen magnum, or orifice through which the brain and spinal marrow communicate, (see a fig. 1,) is not in the centre of the base of

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the skull, but immediately behind it-a position which, as the contents of the anterior part of the cranium have many cavities, while that of the posterior part consists of solid matter, compensates the greater relative specific gravity. It is true that there is still a slight preponderance of the head anteriorly, when all the muscles are relaxed; but this disposition is counteracted by the greater power of the muscles attached to the back of the head, which is sufficiently evident from the fact, that no fatigue is produced by the slight and, we may say, involuntary effort required to keep up the head during a whole day. It will be further seen that this modification of structure adapting man to the erect position, obtains in every part of his frame, and that it belongs to him exclusively.

Compared with the chimpanzé and orang outan, which present the nearest approach to man in general aspect and structure, and which are hence called anthropomorphous or man-like, the foramen magnum, instead of being directly behind the base of

the centre of the skull, occupies the middle of the posterior third, (see a fig. 2,) and this same law holds good as we descend through the scale of mammalia, the foramen gradually approaching the back of the cranium, till finally it is found, as in the horse, nearly in the line of its longest diameter. The points of the skull articulated with the spinal column, are called condyles; and the angle which the surface of these, in man, makes with the horizontal is very small, while in the orang outan it is 37°, and in the borse as much as 90°, their plane being in the last vertical. Hence, if man's natural posture were horizontal, the plane of his condyles would, like those of the horse, be vertical; but that this horizontal position in which man would have the heaviest head with the least power of supporting it, is not natural to him, is plainly evident from the circumstance that, while in other mammalia, the head is supported horizontally by a powerful ligament extending from the back part of the head to the vertebræ of the neck and back, there is scarcely any trace of such a provision in man. It were easy to adduce additional evidence from the head, showing that the erect position is the one exclusively natural to man.

The spine in man, though bent like an italic S, has its curves so arranged that a vertical line from its top, when the body is erect, would strike exactly on the centre of its base-an adaptation which, in the various positions of the trunk, doubtless contributes toward preventing a loss of balance. The column increases considerably in size in the lumbar region, so as to have a pyramidal form, while its base (the sacrum) has a greater proportional breadth than that of any other animal; and as the human pelvis is also remarkably broad, these combined causes still further contribute to maintain the erect attitude. In the chimpanzé and orang, the lumbar vertebræ, which do not increase in size proportionally with that of man, are but four instead of five; and here, too, the processes for the attachment of the muscles to the back are greatly developed in man, while in other mammalia, it is the processes of the vertebræ of the neck and back that are very large and strong, in order to give support by ligaments to the pendent head.

In the accompanying wood-cut (figs. 3 and 4,) exibiting a comparative view of the skeleton of man and the crang outan, the pelvis of the former is very differently constructed from that of the latter a difference observed in all the mammalia beneath man. In the orang, it is much longer and narrower, the sacrum

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