Scheme 2. Illustrating the theory of Continuity of the Germ-Cells; pure germinal inheritance; and the non-transmissibility of acquired characters. The germ-cells are insulated from the body cells. The germ-cell (a) develops into the body-cells, e, e, e, e, and the germ-cells (b), in animal I. The body-cells, e, e, e, e, do not influence in any way the germ-cells (b), as indicated by the absence of perpendicular arrows. The germ-cells (b) get all their heritages from the antecedent germ-cell (a), as indicated by the oblique arrow from (a) to (b). All heritages are purely through the germ-cells. The same with the animals II and III. Germ-cells (a), (b), (c), (d), are connected together by obliquely placed arrows, indicating the continuity of the germ-cells.

Scheme 3. Illustrating the theory of Continuity with Modified Pangenesis. A germ-cell (a) develops into the body-cells, e, e, e, e, and the germ-cells (b) of animal I. The germ-cells (b) get their heritages directly from the germ-cell (a), as indicated by the long, obliquely-situated arrow (continuity of the germ-cells). The germ-cells (b) are, moreover, modified by influences extending from the body-cells, e, e, e, e, as indicated by the perpendicular arrows. A modified germ-cell (b) can develop into a modified animal II, and the body-cells of this animal can influence and modify the germ-cells (c); and so on, indefinitely. The perpendicular arrows indicate that acquired characters are transmitted, and that, too, through the germ-cells.

Professor Morgan, of England, has advanced the ingenious theory, which may reconcile the above-mentioned antagonistic views, that somatic variations, in the direction of adaptation, pave the way for germinal variations, so that, while somatic modifications as such are not inherited, they are yet the favoring conditions under which germinal variations are preserved by the great principle of natural selection. If this is true, as we think it is, then we can safely state that each man in his totality is the resultant of two great factors—heredity and environment, the latter including not only food, water, climate, occupation, etc., but also the character of the civilization, the state of morals in society, the ideals and examples most frequently seen, etc., etc.

Heredity brings down to him the streams of tendency of former generations, often of a healthy and beneficent character, but also often surcharged with lust and passion, and reeking with disease.

Environment is the coöperating and, to us, vitally important factor, inasmuch as it may supplement and thus reënforce the hereditary tendencies, whether good or bad; or it may even tend to turn them into new channels, correcting the evil or vitiating the good.

Man is not simply a creature of the present, but profoundly a product of the past. Bodily structure, moral and intellectual tendencies, disease, vices, and virtues are all in the marvelous stream of heritage that comes to him from the past. “Diseases that no facts in the individual life can account for point gaunt fingers of blame from one generation to another. Not a murderer is hung, not a daughter starts on the downward way, but a great company, like those who were present at the stoning of Stephen, stand by inaugurating and consenting to the ruin.”[4]

Truly has it been said that the past is at work in the present, its powers reaching down through the ages, to all the race, largely molding every human life, touching and influencing every individual’s thought and will, and, more than any other force, coloring history.

Studies in heredity illustrate most luridly that the continuity of the human race is a terrible but remorseless reality.

If the ignorance and the perverted pleasures of one generation may produce the vices and the crimes and the diseases of another, a question of tremendous import arises: Is heredity as potent in the direction of virtue and health as of vice and disease? At the first look one is almost tempted to answer Nay! for the most striking examples of heredity seem to be in the direction of evil. But this is perfectly natural. Decay is always more rapid than growth. A cherry rots much more quickly than it ripens. Vice and disease spread much more quickly and widely than virtue and health. But all history and all social and medical science teach that vice and disease carry within themselves the seeds of decay, and virtue and health the seeds of endurance and growth.

Through the great Darwinian principle of natural selection, or survival of the fittest, vice and disease will become less and less predominant, and virtue and hygienic constitutions more and more disseminated.

As influencing a man’s life and character,[5] which is the stronger factor, heredity or environment? Fatalism or choice? In our opinion, as the result of long study and reading, where we have an average man of “mens sana in corpore sano,” environment will be the stronger factor whether for good or for evil—that is, in men in general, who have no organic defect, such as insanity or idiocy, and allied affections, the stronger force is environment; but in those having such defect, heredity is the controlling power, and, we may add, the destroying power.

It must be recalled, though, that the average man with a “sound mind in a sound body,” in his development to his present estate, has become possessed of a vast aggregate of diverse heritages, of varying age, strength and dignity. Some of them are so old and strong that they seem to be cast in unyielding molds, while others are so weak and recent that they fluctuate with every passing circumstance. The most dignified and important of all his heritages is that of rational volition. It is the play of this volition upon many of his other heritages that gives him the power of selecting, to a limited extent, his environment.

Every man is born into the world with a certain physical constitution, and, therefore, with a given temperament; with certain passions; with the power of judgment; and with a certain strength of will. If the power of his will be not equal to the strength of his passions, the latter will surely predominate and will display him as the slave of heredity. If he has such an organization of his nervous system that his volition is superior to his passions, he will be none the less the servant of heredity, though a being now possessed of the power of Free-Will.

Man is, to a far greater degree than is ordinarily realized, the servant of heredity. It seems to us an incontrovertible fact that every living creature, at any given moment, is swayed infinitely more by the totality of its heritages than by its environment. No one can possibly deny this so far as plants and most animals are concerned. Nor, if one look below the surface, can it be denied of the higher animals and of man. Happily, the average man, with his present constitution, has his diverse heritages so proportioned that we may repeat that his life and character (in customs, morals, and religion) are vastly more influenced by environment than by heredity.

The standards for estimating the life and character of men, namely, human customs, morals, and religions, are such recent acquisitions, geologically speaking, that they have, as yet, very slightly if at all influenced the germ-cells. They are acquired (somatic) characteristics, and not congenital (germinal) qualities. They are preëminently the creations of environment. If the infants of a Catholic family which is descended from a long line of Catholic ancestors were to be placed and retained in a purely Mohammedan environment, heredity would carry no Christian customs, morals or religion into that environment, but, on the contrary, the Mohammedan surroundings would instill new customs, different ethical ideas, and a different religion. This illustrates how very feebly indeed are germ-cells correspondingly impressed by pure acquired characters. It is almost certain that the translation of somatic changes into germinal changes is appallingly slow. As far, then, as social customs, morals, and religion are concerned, the average man is, in our opinion, infinitely more the creature of nurture than of nature. But, as far as his temperament, his emotional nature, his judgment, his strength of will, in short, his physical and therefore his mental constitution, are concerned, he is almost absolutely the creature of heredity. The equilibrium of qualities or heritages in the average man, resident in a given, stable community, is in harmony with the average customs, ethical ideas, and religious beliefs of that community. But in all stable communities there are men whose resultant of heritages, some in one direction and some in another, places them out of harmony with the average of their social environment, and they are looked upon, some as idiots, some as geniuses, some as criminals, and others as saints, and so on. So that again we may say that a man’s character in a community is the resultant of an hereditary physical constitution, and his environment. Some men may inherit such a physical constitution that in spite of the best environment they are much debased below the average man; others may possess such heritages that, notwithstanding adverse circumstances, they reach a level of character much above the average man. And there are all gradations between the two extremes.