COLLATERAL READINGS SUGGESTED

IN CONNECTION WITH ESSAY XII.

Darwin's Origin of Species; Haeckel's History of Creation, and Evolution of Man; Spencer's Biology; Fiske's Cosmic Philosophy and Excursions of an Evolutionist; Huxley's Letters on Evolution and Critiques and Addresses; Romanes' Scientific Evidences of Organic Evolution; Wallace and Dyer's The Distribution of Life; Schmidt's Doctrine of Descent and Darwinism; Cazelle's Outline of the Evolution Philosophy; Professor Morse's Presidential Address before the American Association for the Advancement of Science, 1887.

PROOFS OF EVOLUTION.*

EMERSON says: "Beware when the great God lets loose a thinker on this planet. Then all things are at risk." This laconic saying has been more than verified within the last thirty years. The thinkers have been holding high carnival; - and all about a little protoplasmic cell that none of them could see with the naked eye.

Two great questions have always been before the world: one, as to the beginning of all things; the other, as to the end of all things. Concerning these two problems, many sacred books have been written, from which a dozen great religious systems have sprung, all setting forth, more or less minutely, theories of the genesis of mind and matter. The explanations thus given, though crude and barbarous in many of their features, have been generally accepted, and the races of men have shaped their earthly careers in accordance therewith. Now and then a splendid soul arose and denied the truth of these assumed revelations; but he rarely lived to. repeat the denial.

For ages men were content merely to know how to utilize the simplest forces of nature, to learn how to do the commonest things, and to join in communities for pleasure and protection. They thought all things were made out of hand by a Supreme Architect who directed momentarily and minutely all human affairs. Fear and wonder made all their gods, and love and hope supplied them with the beautiful belief in immortality.

Although the martyrs of truth fell one by one, each left a germinal thought behind. Only within the present generation has it become safe and reputable to think. Hardly is this even now the exact truth; for the "Descent of Man was at first hailed with good natured laughter and gentle derision; it was a good drawing-room joke at the expense of the monkey tribe. Even at the present moment, the vast majority of the people smile broadly whenever the subject

* COPYRIGHT, 1889, by The New Ideal Publishing Co.

of man's evolutionary origin is seriously mentioned. Comparatively few as yet accept all that is implied in the doctrine of Evolution. Nevertheless, it is bound up in one way or other with nearly every branch of human knowledge. The word is in every mouth. The fact connects itself with every known phenomenon. The greatest foe to the development theory has naturally been the church; because if Evolution is true, theology must be reconstructed in accordance with the principle of the supremacy of law and the impossibility of its violation by the intrusion of miracle. Not until there are more Scientific and Ethical Associations, and not until schools and colleges teach the doctrine of Evolution, will it become imbedded in the thought and life of the masses.

It may be, and often has been, asked, "Of what use is all this knowledge? What is the practical benefit of believing that man began life as a Moneron, and by strict attention to business has worked himself up to his present high estate the paragon of animals'?" In the first place, all this is worth knowing for truth's own sake, since every truth contains the germ of good, and wherever it leads, all may safely follow. But the practical benefit which the knowledge of Evolution conveys, influences man in all relations of life, as an individual and as a member of society. First of all, it teaches him the great lesson of reliance upon law that all things are the result of growth and development; that the present is the child of the past, the simple the germ of the complex. It teaches the impossibility of the fortuitous and the miraculous,—that if we expect effects, we must set in motion adequate causes; that to live wisely and well, we must adjust ourselves to the natural and rational.

While it does not take away one rational hope, Evolution sweeps into oblivion all the childish fables of the past; it points to a new heaven and a new earth; it bids us awake from our pretty dream of the supernatural, and work in, with and through Nature, if we would make the wilderness. of woe and wrong to blossom as the rose. It has unified all science and given learning a new force and meaning. It has added vastly to the sum of knowledge, and to the aggregate of human happiness.

In all its branches and bearings, it directly tends to enlarge and intensify human love and sympathy, and so stimulates.

the forces that lead to industry and thrift, and on to the highest plane of moral well-being.

It teaches the principles of adjustment and harmony; it bids us always to take thought for the morrow, and proclaims that love and labor united constitute the "divinity that shapes our ends." It will make the world more generous, kind, and charitable; more patient, brave and true; more humble, gentle, and unselfish; more noble, virtuous and patriotic. It will do all this because it asserts the great law of mutual duty. Evolution affirms the survival of the fittest. It prophesies even better things to come, than those which we now know. It points toward an ideal of perfection. Its flower and fruitage in life is moral grandeur.

Admitting its scope and possibilities, as thus portrayed, we are now at the threshold of the vital question, "Is Evolution true?" For nothing false can be a permanent good. This question must be answered briefly and imperfectly; for an hour gives time barely to mention the various phases of the great theme. We are compelled to take a hasty view of the broad field, touching only the mountain peaks in the line of proof which establishes the theory of Evolution.

What is Evolution? A late writer has tersely defined it as follows: "Evolution is continuous, progressive change, according to certain laws, and by means of resident forces." Evolution is simply growth and change, governed by fixed laws. Its corner stone is continuity.

The Essayists who have preceded me have explained to you Solar and Planetary Evolution, as also the Evolution of the Earth as a whole, of Vegetal and Animal Life, of Mind, of Man, of Society, Theology and Morals. It is in the field of Biology, however, that the proofs of Evolution are most abundant and conclusive. To this line of proof I shall mainly confine my attention. But before proceeding to details, it may be well to point out the

FOUR GREAT FACTORS OF EVOLUTION,

on which the entire theory rests. These are (1) The influence of Environment; (2) The increased use or disuse of organs; (3) Natural Selection, or Survival of the Fittest; and (4) Sexual Selection. The two former are accredited to Lamarck and others, but the two latter are wholly Darwinian; and running through all is the potent influence of heredity.

A change in environment effects a corresponding change in functional activities, which leads to structural modification. Common observation and experience show us the effect of the use or disuse of an organ or part. This is likewise observable in determining the greater or less acuteness and activity of all the senses. An organ lying dormant during many generations will gradually atrophy, and appear as a rudiment, finally vanishing altogether. Fishes and animals dwelling in underground caves into which no light enters, are sightless, as they have no use for eyes. They have lost them by disuse. The wonderful development of the gymnast and athlete is achieved by intensified use of the muscular system. If use or disuse is continued from generation to generation, heredity will transmit the result.

Natural Selection, or Survival of the Fittest, grows out of the struggle for self-preservation. It is based on the law of hunger. It develops strength, cunning, or agility. It is an enemy to the weak and poorly conditioned. We see this principle exemplified every day in the struggle for supremacy among individuals, communities, nations, and races. The strongest and best-favored survive; the weakest perish.

Sexual Selection is not concerned with hunger, but with beauty and the desire for offspring. As well stated by Prof. LeConte, "In Natural Selection there is a struggle of all for food, or means of living. In Sexual Selection there is a struggle among the males for the possession of the females and the means of procreation. The one is related to the nutritive appetite, the other, to the sexual appetite."

In animal life, Natural Selection most obtains among mammals; sexual selection is more predominant among birds, those having the most beautiful plumage, or sweetest songs, winning the choicest mates. The former fight for existence; the latter, like the warriors bold of the Middle Ages, battle for love. This warfare is in the world to-day wherever there are life and movement. These principles of evolution are still everywhere operating. Heredity preserves these jewels of descent, without which we would go back to "chaos and old night.'

PROOFS FROM GEOLOGY.

Among the strongest proofs of Universal development, are those drawn from geological study. The earth has en