III. Man a Mammal.

Man is a mammal. He belongs to the most brilliant and influential of the five classes of vertebrates—the class to which belong so many of his associates and victims, the class to which belong the horse, the dog, the deer, the ox, the sheep, the swine, the squirrel, the camel, the unattenuated elephant, and the timid-hearted hare. To this class belong also the lion, the tiger, the kangaroo, the beaver, the bear, the bat, the monkey, the mole, the wolf, the ornithorhynchus, and the whale—in short, all animals that have hair. Fishes and reptiles have scales; birds have feathers; all mammals are covered to a greater or less extent with hair. The aquatic habits of whales render hair of no use to them. Hence, while the unborn of these animals still cling to the structural traditions of their ancestors and are covered with hair, the adults are almost hairless. The sartorial habits of human beings and the selective influences of the sexes have had a similar effect on the hairy covering of the human body. Hair exists all over the human body surface, excepting on the soles of the hands and feet, but in a greatly dwarfed condition. It is only on the scalp and on the faces of males, where it is scientifically assisted for purposes of display, that it grows luxuriantly. It is by no means certain that even the hair on the masculine scalp will last forever. For if the hermetical derby and other deadly devices worn by men continue their devastations as they have in the past, we may expect to have, in the course of generations, men with foreheads reaching regularly to the occiput. Most animals lay eggs. Man does not. Like the dog, the horse, the squirrel, and the bat, man is viviparous, the eggs hatching within the parental body. Human young are born helpless, and are sustained during the period of their infancy by the secretions of the milk glands. So are all the sons and daughters of mammals. Whether they come into the world among the waters or among the desert sands, in the hollow of a tree, in a hole in the earth, or in a palace, the children of mammals are frail and pitiful, and they survive to grow and multiply only because they are the object of the loving and incessant sacrifices of a mother.

Mammals are distinguished from all other animals by the possession of two kinds of skin glands—the sweat glands and the oil glands—and by the development of certain of these glands in the female into organs for the nourishing of the young. Among reptiles and birds the lower jaw is suspended from the skull by a bone called the quadrate bone. Among men and other mammals the lower jaw is joined directly to the skull, the quadrate bone becoming, in the vicissitudes of evolution, the hammer (malleus) of the mammalian ear. Man has a four-chambered heart—two reservoirs which receive, and two pumps which propel, the scarlet waters of the body. Fishes have two-chambered hearts; frogs and most reptiles have three-chambered hearts; all mammals and birds have four-chambered hearts. The red corpuscles in the blood of fishes, frogs, reptiles, and birds, are discs, double-convex, nucleated, and in shape oval or triangular. In man and in all other mammals (except the archaic camel) the red corpuscles are double-concave, non-nucleated, and circular. ‘Man has a diaphragm dividing the body cavity into chest and abdomen, and a shining white bridge of interlacing fibres, called corpus callosum, uniting his cerebral hemispheres. And man is a mammal because, like other mammals, he has, in addition to the qualities already mentioned, these valuable and distinct characteristics.

IV. Man a Primate.

Man is a primate. There are four divisions in the order of primates—lemurs, monkeys, apes, and men. But the most interesting and important of these, according to man, is man. Man is a primate because, like other primates, he has arms and hands instead of fore-legs. And these are important characteristics. It was a splendid moment when the tendencies of evolution, pondering the possibilities of structural improvement, decided to rear the vertebrate upon its hind-limbs, and convert its anterior appendages into instruments of manipulation. So long as living creatures were able simply to move through the airs and waters of the earth and over the surface of the solids, they were powerless to modify the universe about them very much. But the moment beings were developed with parts of their bodies fitted to take hold of and move and fashion and compel the universe around them, that moment the life process was endowed with the power of miracles. With the invention of hands and arms commenced seriously that long campaign against the tendencies of inanimate nature which finds its most marvellous achievements in the sustained and triumphant operations of human industry. None of the primates excepting man use their hind-limbs as a sole means of changing their place in the universe, but in all of them the fore-limbs are regularly used as organs of manipulation. Man is a primate because his fingers and toes, like those of other primates (except the tiny marmosets of Brazil), end in nails. Man has neither claws to burrow into the earth, talons with which to hold and rend his victims, nor hoofs to put thunder into his movements. The human stomach, like that of all the other primates, is a bagpipe. The stomach of the carnivora is usually a simple sack, while rodents have, as a rule, two stomachs, and ruminants four. Man is a primate because his milk glands are located on the breast and are two in number. The mammary glands vary in number in the different orders of mammals, from two in the horse and whale to twenty-two in some insectivora. Most ruminating animals have four, swine ten, and carnivora generally six or eight. These glands may be located in the region of the groin, as in the horse and whale; between the forelimbs, as in the elephant and bat; or arranged in pairs extending from the fore to the hind limbs, as in the carnivora and swine. In man and all other primates (except lemurs) the mammary glands are pectoral and two in number. All primates, including man, have also a disc-shaped placenta. The placenta is the organ of nutrition in mammalian embryos. It is found in all young-bearing animals above the marsupials, and consists of a mass of glands between the embryo and the parental body. In some animals it entirely surrounds and encloses the embryo; in others it assumes the form of a girdle; and in still others it is bell-shaped. The primates are the only animals in which this peculiar organ is in the shape of a simple disc.[1]

The nearest relatives by blood man has in this world are the exceedingly man-like apes—the tailless anthropoids—the gorillas and chimpanzees of Africa, and the orangs and gibbons of southern and insular Asia. The fact that man is an actual relative and descendant of the ape is one of the most disagreeable of the many distasteful truths which the human mind in its evolution has come upon. To a vanity puffed, as is that of human beings, to the splitting, the consanguinity of gorilla and gentleman seems horrible. Man prefers to have arrived on the earth by way of a ladder let down by his imagination from the celestial concave. Within his own memory man has been guilty of many foolish and disgraceful things. But this attempt by him to repudiate his ancestors by surreptitiously fabricating for himself an origin different from, and more glorious than the rest is one of the most absurd and scandalous in the whole list. It is a shallow logic—the logic of those who, without worth of their own, try to shine with a false and stolen lustre. No more masterly rebuke was ever administered to those in the habit of sneering at the truth in this matter than the caustic reply of Huxley to the taunt of the fat-witted Bishop—that he would rather be the descendant of a respectable ape than the descendant of one who not only closed his eyes to the facts around him, but used his official position to persuade others to do likewise. Man’s reluctance to take his anatomical place beside his simian kinspeople has been exceeded only by his selfish and high-handed determination to exclude all other terrestrial beings from his heaven.

Man is a talkative and religious ape. He is an ape, but with a much greater amount of enterprise and with a greater likelihood of being found in every variety of climate. Like the anthropoid, man has a bald face and an obsolete tail. But he is distinguished from his arboreal relative by his arrogant bearing, his skilled larynx, and especially by the satisfaction he experiences in the contemplation of the image which appears when he looks in a mirror.

The man-like apes are from three to six feet tall, and are all of them very strong, the gorilla, who sometimes weighs over three hundred pounds, being about the bravest and most formidable unarmed animal on the planet. They are erect or semi-erect, have loud voices, plantigrade feet, and irritable dispositions—in all of these particulars being strikingly like men. The gorilla, chimpanzee, and gibbon are highlanders, preferring the uplands and mountains. The orang is a lowlander, living phlegmatically among the sylvan swamps of Sumatra and Borneo. The gorilla and chimpanzee are terrestrial, seldom going among the trees except to get food or to sleep. The orang and gibbon are arboreal, seldom coming to the ground except to drink or bathe. They all walk on their hind-limbs, generally in a stooping posture, with their knuckles or fingers touching the ground. But they sometimes walk with their arms hanging down by their sides, and sometimes with their hands clasped back of their heads to give them balance. None of them ever place their palms on the ground when they walk—that is, none of them walk on four feet. The anthropoid races, in the shape of their heads and faces and in the general form and structure of their bodies, and even in their habits of life, resemble in a remarkable manner the lowest races of human beings. This resemblance is recognised by the negro races, who call the gorilla and chimpanzee ‘hairy men,’ and believe them to be descendants of outcast members of their own species.

There are differences in structure between man and the apes, just as there are differences in structure between the Caucasian and the Caffre, or even between individual Caucasians or individual Caffres. There are differences in structure and topography, often very noticeable differences, even among members of the same family. But in all of its essential characters, and extending often to astonishing particulars, the structure of man is identical with that of the anthropoid.[2]