PERSONAL IDENTITY.

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It is believed that not a single particle of matter which is in the child remains in his body till adult life is reached. But the wonderful fact remains that the individuality or personal identity continues though every particle of the matter of the body has been changed. What is this wonderful entity which preserves personal identity, and makes one still the same person though all else has been changed? Can it be other than a living force?

CHAPTER VII.

THE DEVELOPMENT OF LIFE.

THIS chapter is chiefly devoted to further examination of various theories of the development of life.

An actual fact is not changed, whether it is stated by one who is learned or by one who is comparatively ignorant, — the fact still remains eternal truth.

Agassiz believed that an almighty creative intelligence established the very laws of nature themselves. Had Agassiz yielded to the demands of that class who do not believe that a being of infinite intelligence was the originator of earthly existence, and taught that species came to exist through the laws of nature without the intervention of a creator, might he not have passed with them for a distributor of opinions of the highest scientific value? But every person who was fortunate enough to be acquainted with that gifted naturalist is convinced that he taught only what he believed to be true.

closed

Hæckel writes, p. 117: "When, in 1873, the the grave over Louis Agassiz, the last great upholder of the constancy of species and of miraculous creation, the dogma of the constancy of species came to an end, and the contrary assumption the assertion that all the various species descend from common ancestral forms now no longer encounters

serious difficulties."

Suppose "that the assumption that all the various species descended from common ancestral forms now encounters no

serious difficulties in consequence of the death of Agassiz, does not that very statement seem to imply that the validity of that doctrine might be in some measure dependent upon the teachings of men? What difference could the living or dying of any man make as to the truth or falsity of actual facts?

By constancy of species Agassiz meant that there has been no change of one species into another. Thus, he taught that lions are descendants of lions, or some ancestor of the cat family; and sheep of sheep from their first creation, and that the descendants of lions will be lions, and the descendants of sheep, sheep, etc., and that these animals will never in the future change into any other race of animals essentially different from the present races.

He taught that the ancestors of men were men from their earliest creation, and their descendants, to their latest posterity, will also be men with mental and physical characteristics essentially like those now living.

Most of those who indorse the theory of man's descent from an original one-celled ancestor contend that there is a continuous line of development by the laws of nature.

It should be borne in mind, however, that there are many firm believers in the doctrines of evolution who also firmly believe that an almighty creative intelligence established the laws of development, and that what we call the laws of nature are only the manifestations of his manner of working.

Concerning Lamarck's theory, Hæckel writes, vol. 1, "Evolution of Man," p. 85: "Lamarck was the first to formulate the scientific theory of the natural origin of all organisms, including man, and at the same time to draw the two ultimate inferences from this theory; firstly, the doctrine

of the origin of the most ancient organisms through spontaneous generation; and, secondly, the descent of Man from the Mammal most closely resembling Man, the Ape."

In attempting to explain how this came about, "he considered that, on the one hand, practice and habit (adaptation), and, on the other, heredity, are the most important of these causes."

On page 86 he adduces examples as follows: "To mention examples, the Woodpecker and the Humming-bird owe their · peculiarly long tongue to their habit of using these organs to take their food out of narrow and deep crevices; the Frog acquired a web between its toes from the motions of swimming; the Giraffe gained its long neck by stretching it up to the branches of trees." "Lamarck fully perceived that Heredity must necessarily coöperate with Adaptation."

To sum up, he contends that the first step made by apes towards becoming men, was when they gave up the habit of climbing trees, and "accustomed themselves to an upright gait." This exercise developed the spine and the pelvis ; and the fore-legs, instead of being used for climbing, developed into arms and hands for the "purpose of grasping and touching," while the hind pair were used for walking, and their extremities were developed into true feet. In consequence of the totally changed mode of life," there came a change of jaws and teeth, and, consequently, of the whole shape of the face. The tail, no longer needed, disappeared. Then, as the apes began to live in communities, social instincts developed, and family relations began to subsist, and the apes' language of sounds developed into the language of Then the brain changed its shape, and grew men, etc. larger by its more constant use, etc.

"These important ideas of Lamarck contain the first and oldest germs of a real history of the human tribe."

To give the reader as clear an idea as possible of the theories of Lamarck and others of his school in a small compass, I will quote a summary from Dr. Edward Hitchcock ("Religion of Geology," pp. 289, 290): "The French zoologist, Lamarck, first drew out and formally defended this hypothesis, aided by others, as Geoffroy St. Hilaire and Bory St. Vincent. Their supposition was that there is a power in nature, which they sometimes denominated the Deity, yet did not allow it to be intelligent and independent, but a mere blind, instrumental force. This power, they supposed, was able to produce what they called monads, or rough draughts of animals and plants. These monads were the simplest of all organic beings, mere aggregations of matter, some of them supposed to be inherently vital. And such monads are the only things ever produced directly by this blind Deity. But in these monads there was supposed to reside an inherent tendency to progressive improvement. The wants of this living mass of jelly were supposed to produce such effects as would gradually form new organs, as the hands, the feet, and the mouth. These changes would be aided by another principle, which they called the force of external circumstances, by which they meant the influence upon its development of its peculiar condition; as, for instance, a conatus for flying, produced by the internal principle, would form wings in birds; a conatus for swimming in water would form the fins and tails of fishes; and a conatus for walking would form the feet and legs of quadrupeds. Thus the organs were not formed to meet the wants, but by the wants of the animal and plant. Of course, new wants would produce new organs; and thus