THE DESCENT OF MAN.* THE modern doctrine of evolution is that theory of the origin of things as they now appear, which does not involve the introduction of energy from without. In this respect it is contrasted with the conception of creation. In biology it ranks man as one of the animals -the highest animal, if you please, but still an animal. The genealogy of man is therefore included with that of all species of animals. When the highest class, Mammalia, was developed, the possibility of man resided in it. Man is a vertebrate and a mammal. The curiosity developed by the perception of man's evident relation to other Mammalia has been answered by the discovery of the law of Evolution. We have now pretty nearly a complete record of the descent of man. Low down in the genealogical line of man are certain of the marsupials, or pouch-bearing Mammalia, which bring forth their young in a very immature condition, and carry and nourish them in a pouch until they become. able to walk. These survive now only in Australia, and in the opossum of the Americas, though formerly they prevailed over the whole world. Above the Marsupialia are the Condylarthra, and from these branch out in one direction the groups of ungulate mammalia-the hoofed quadrupeds-including the Proboscidia, the Amblypoda, and the Diplarthra; which latter are in turn separated into the two sub-orders of Perissodactyla and Artiodactyla --those which divide the hoof, and those, like the horse, which walk principally upon a single median hoof. In another direction. are developed the Unguiculata or clawed quadrupeds, which are divided into the Bunotheria, the Carnivora, or meateaters, the Edentata, the Chiroptera and the Rodentia. The human type is nearer to the hoofed type than to the clawed type, and branched off from the Condylarthra in a separate direction. Man is not developed from any existing order of anthropoid apes, though both belong to the sub * COPYRIGHT, 1889, by The New Ideal Publishing Co. order Anthropomorpha, of the order Quadrumana, to which all the ape family belong. Man's ancestors, however, branched off from the ancestral line as low down as the lemurs, once prevalent mammalia in North America, but now nearly confined to Madagascar, and which greatly resemble the Condylarthra. From the lemurs we trace the monkeys proper, and then the anthropoid apes, which come nearest to man of all the mammalia. Their vertebræ differ from those of the monkeys, and resemble human vertebrae. In the brain, also, they are nearer the type of man than of the monkey. They have the third convolution of the frontal lobes, which in man is the seat of the power of language, and which is wanting in the monkeys proper. But the difference between these apes and man is considerable, if we leave generalities and confine ourselves to details. constitute in fact a separate family, the Simiidæ, though belonging to the same sub-order. In the sub-order Anthropomorpha there are but the two families — the anthropoid apes and man. The sole external anatomical difference is the great toe, which in the apes is opposed to the other toes, while in man it is parallel with them. In man the last true molars (wisdom teeth) are protruded after the appearance of the canines. In apes and monkeys the wisdom teeth appear before the canines are fully in place. But remains of a monkey have been discovered in Europe in which it is thought that the wisdom teeth are yet unprotruded, although the canines have reached their full development. This is the Dryopithecus fontani, an ape of about the size of man. They This, then, is the general view of the later stages of the genealogy of man. Those lines of descent in the Vertebrata carry within themselves the evidence that they have followed definite directions toward mechanical perfection, and attained definite results. We see this in the development of the limbs and of the other organs which tend to enable each group to live in the best possible manner. The Bunotheria, for example, have acquired claws, as a means of defense, and as an aid in climbing. The Rodentia have a different means of defense: they dig holes and thus escape from their pursuers. The bats have developed wings, and fly away. The lowest group, structurally, are the Edentata, whose general habit is to excavate for defense. The hoofed mammalia have developed powers of rapid locomotion, and can run away from their enemies. In the quadrumanous group we find none of the special characteristics of the others but it has triumphed in the struggle for existence, as this audience shows. Man has neither fleetness nor fossorial abilities. His ancestors took to the trees and found in an arboreal life both greater safety and abundance of food. They trusted to their wits instead of to fleetness or strength, and became the most inquisitive and intelligent of animals. Monkeys resemble man in these respects far more closely than other animals even the intelligent dog or horse. All monkeys are exceedingly suspicious, and that indicates wisdom. When tamed, they have a remarkable power of readily discovering the state of mind of their masters. Anthropoid apes are also intelligent, but for various reasons their habits have not been studied as closely as those of monkeys. The defenceless condition and social habits of the Quadrumana have been, it is thought, the means of the development of their intelligence to a point which has made the human intellect possible. As to the period of geological time in which man first appeared, there is much doubtful evidence. We have some evidence of his existence in Europe, where the ground has been more thoroughly investigated than elsewhere, before the glacial period. Flints, to all appearances artificially manufactured, have been discovered by the Abbe Bourgeois in the Middle Miocene of France, which may have been made by man. As an alternative Prof. Gaudry suggests that they may have been made by the Dryopithecus. In America palæolithic flints have been found in the glacial gravels of the Delaware valley, and, as I believe, in the upper Pliocene beds of the West and South West. William Taylor has found palæolithic implements in the same bed with Glyptodon and extinct species of horses in S. W. Texas. Ameghino has found human bones in the Upper Pliocene of Buenos Ayres. We find also the remains of primitive races in caves, as at Neanderthal and elsewhere, and they have been collected in sufficient numbers to show that some of them represent a race distinct from all existing races, the lowest type of man we know, while others do not differ materially from modern types. Their anatomical characteristics are similar to those of the anthropomorphous apes as indicated by the thickness of the skull and lower jaw, the flatness of the tibia, etc. Man is the only quadrumanous animal possessing a chin. In the jaws of some of these cave-men the chin is almost wanting. A recent discovery of human remains of the pre-Indian period in Arizona, goes to show that primitive man was deficient in speech, as these skeletons retain the primitive distinction of other speechless mammalia, in having the hyoid bones separated. In man as we now know him, these bones are consolidated, forming a single bone. The general theory of descent rests upon the study of species in detail. There can be no doubt in the mind of the student that the specific lines of definition are movable. Each species has stages of variability, when it is comparatively plastic, and susceptible of change, before it has developed an unyielding contour and form. Afterwards they develop into fixed types, and do not evolve into other species thereafter. This is the condition in which we find most of the animal forms at the present day. Our cats, for example, are not variable, or are variable only within specific limits. Dogs, on the contrary, are very variable, and so are barn-yard fowls. Mankind is in a condition of plasticity or variability, and herein lies great promise of human progress in the future. In attempting to account for the evolution of man, we have two theories, one of Lamarck and the other of Darwin. Lamarck devoted himself to explaining the origin of species, but not to the special problem of natural selection. The post-Darwinians, as they have been happily named by Romanes, have generally accepted Darwin's hypothesis as a complete explanation of evolution, but we are beginning to see that Lamarck's views cannot be set aside, and that it is of great importance in explaining the origin of variations. Without it, natural selection would have no opportunity for operation. The Darwinians say that animals and plants have a tendency to variation. But nothing happens accidentally — there can be no variation without a cause. Seeking out these causes of variation is the province of a certain school of biologists at the present time. To this study, the great nations of the world are all contributing. Chemistry has been called a French science. In embryology Germany stands at the head. Palæontology will doubtless constitute the contribution of America to this investigation. A rich field for this investigation exists in our Western States and territories, rivalled only by a similar field in the Argentine Republic. The fact that the earth cooled first at the poles, I suggests that life began independently at each pole, and thence spread to other portions of the earth. Future investigations in the Argentine Republic are likely to throw much light on this theory, which cannot yet be said to be established as regards vertebrate animals. Following the line of descent, we find that many lines of progress have maintained themselves, and that these lines are not accidental or arbitrary. Here and there, indeed, we find that some magnificent capabilities have been switched off the track; and for these progress has ceased. In other cases retrogression has taken place. A profound lesson may be drawn from the observation of this fact. We may be thankful that our ancestors got on the right track; and if we did come from a humble origin we can rejoice in what we have attained, and reflect upon what we may escape in the future. The origin of variations can be traced to varied causes, and modifications are almost always explainable by careful study. The object of all things is to live; and to secure the means of living is the end which they aim to accomplish. The motion consequent upon this effort is the active, and the environment the passive factor in development. One of the first principles in progress is the capacity to move from place to place. Those animals which become sessile, or fixed to one spot, cease to progress, and tend rapidly to retrograde. The structural changes are induced by contact with environing conditions, and by motion. There is progressive evolution, and also retrogressive evolution; progress and degeneration. The competition of the struggle for existence compels excellence. The absence of it tends to inactivity and degeneracy. Groups have thus arisen, and then fallen. The result on the whole has been a constant advance since the beginnings of life on the earth; but the number of degenerate lines is nevertheless very great. The Lamarckian view that structure results from use is undoubtedly correct. In this way certain mechanical causes have induced changes in the skeletons and teeth of vertebrate animals. These hard parts determine the character of the entire organism, the softer portions conforming to them and being modified in the directions which their changes indicate. The original impulse is in the activity of the animal. If all animals had been created alike they would at once have begun to act differently, and modifications would |