HEREDITY.

It may be remarked, in a general way, that the subject of heredity is one of profoundest significance in its relation to society. Through its influences the peculiarities and characteristics of families and nations are largely developed and perpetuated. It “is that biological law by which all beings endowed with life tend to repeat themselves in their descendants.”[9] It depends upon “an internal principle of vitality” which is so engraven upon every portion of the system before birth, that its influence remains through life, and within certain limits pertains alike to both the physiological and psychological nature. Not that this influence is such, or operates in such a manner, as to repeat itself in any stereotyped form, but rather in an endless variety of forms; while no child resembles its parents in all respects, yet there ever occurs a blending of the characters of both parents, together with a large number of those characteristics which have, for long generations, been interwoven in multiform shades and degrees in ancestors.

Passing now from the general to the particular, we find, first, in reference to physiological characteristics and peculiarities, that these tend to repeat themselves more or less directly, so that when they have once appeared, they may, with reason, again be expected. Peculiarities of the fingers and toes, of the hair, the shape of the head, the conformation of the face, and even particular portions of the face, remain for long periods in the same family and nations. The characteristic form of face and nose peculiar to the Jew, is an example in point, and so invariable as to lead to recognition, in spite of the changes and vicissitudes incident to travel and residence during many hundreds of years, under climatic conditions of large diversity, and ofttimes experiences of great and protracted severity.

Not only are such peculiarities as may be considered normal transmitted, but also such as are abnormal,—a supernumerary finger or toe, or a mole on some portion of the face or part of the body. A supernumerary finger or toe may be transmitted for at least four generations, though not to every member of the family, and the experiments of Mr. Darwin, with birds, go to show that the tendency to perpetuate such a peculiarity, exhausts itself after a few generations, the type returning to its original character.

Fecundity is also well known as an inherited character. A mother is referred to by Girou,[10] as having had twenty-four children, five of whom, in turn, gave birth to forty-six. A granddaughter of this woman gave birth to sixteen. The females of some families have all or nearly all daughters, who, in turn, have more daughters than sons for several generations. A grandmother had nine daughters, several of whom had no sons in the third generation.

Longevity has long been recognized as one of the most transmissible of family traits.

CÆteris paribus, persons connected with long-lived families have a much more tenacious hold on life than others: the capacity for resisting the changes of climate, the morbific conditions of the atmosphere and soil, the influences of epidemic diseases, and the experiences of privation and hardships, is greater than with other persons; and, conversely, the capacity for resisting these influences is much less with persons whose ancestors have invariably died at an early age.

So also if a person resembles in physical form, complexion, and constitution, the ancestors of one side of his family who have lived to old age, while those on the other side have died comparatively young, his prospects of longevity are generally strengthened in proportion to the extent of such resemblance. M. Levy says: “To be born of healthy and strong parents is to have a good chance of longevity; the energy of the constitution is the best buckler against the assault of destructive causes. Rush did not know an octogenarian whose family did not offer many examples of advanced old age. This observation, made by Sinclair, has acquired the force of an axiom, so common is it to meet with longevity as a frequent occurrence among many members of the same family. Inheritance exercises the same influence on the total duration of life of short period: in the Turgot family scarcely a member passed the fiftieth year; he, who rendered it illustrious, died at the age of fifty-three, in spite of the appearance of great vigor of temperament.”

So familiar to every one are the facts connected with the transmission of morbid physiological processes, that I need not refer to this point further than to remark, that the phthisical, the cancerous, and the scrofulous diatheses are those well known to be more surely inherited, and that through these channels of diseased action whole families cease to exist after two or three generations, unless the tendency is counteracted by more vigorous and healthy influences from the other parent.Passing now to the psychological traits and characters, we observe that the same law pertains. The heredity of mental qualities is quite as persistent as that of the physical; imagination, memory, will, intellect, the sentiments and passions, may all be inherited. It is estimated that not less than forty per cent. of eminent poets have had illustrious relatives. The families of Darwin, Cuvier, Bacon, Sir Benjamin Brodie, John Adams, Lord Macaulay, Madame de StaËl, present good illustrations of the inheritance of intellectual ability.

But no less surely are the characteristics of morbid mental activity transmitted from one generation to another. The records of asylums all indicate that the tendency to insanity, in some of its forms, is one of those most likely to be inherited. It is thought that more than one half of the admissions to English asylums present evidence of an inherited taint. The same is probably true in reference to admissions to asylums in the United States, though it is exceedingly difficult to arrive at the truth in all cases, inasmuch as many persons are inclined to deny that any such tendency exists in their families, lest such a fact should appear to its prejudice in some way or other.

It is not the case, however, that definite forms of insanity always repeat themselves, but, on the contrary, change, so that a case of mania may appear in the second generation as a case of melancholia, or acute dementia; and, vice versa, melancholia may appear as dementia. Information concerning the inheritance of general paralysis is not so definite; indeed, this form of insanity generally manifests itself in those having no tendency by inheritance, and would seem to be more frequent among the strong and robust, and also has a tendency to appear in the very prime of life.

It is not necessary that the tendency toward unstable mental action should be fully developed in the parent in order that it may so appear in the child. Parents who have for years been very odd or singular in their habits of life and manner of speech and mental operations; those who are subject to periods of depression, and are accustomed to look upon the dark side of daily experiences; mothers, more often, perhaps, who have all their lives been “nervous” or irritable and easily excited, impress more or less profoundly these abnormal conditions upon their offspring. Great singularity of conduct habitually displayed, periods of depression, irritableness, and nervousness, when crossed with similar characteristics in the other parent, or other unusual ones, not infrequently develop into actual insanity in succeeding generations.

A good example of such a tendency is related in the April No. of the Journal of Mental Science, 1881.[11] It began on the male side, the father being “eccentric” or “peculiar,” so much so as to attract the attention of the village children. The wife had no peculiarities of sufficient import to be marked. They had four children, three of whom were affected mentally, one female and two males. The female was “uncommon” and “slightly weak-minded.” One of the males was said to have been “weak-minded”; the other was “strange-looking,” and odd in general conduct. He married a woman in good health and free from any special tendency, either mental or physical. There were born eleven children: of these, five were imbecile; two were idiots, and the remaining four were sane. Of these four, two had one child each, one of whom died of phthisis, and the other is at present an imbecile.

A consumptive parent may have children who are free from this particular form of diathesis, and yet at some period of life may be affected with insanity; or parents with an insane diathesis may have offspring who are tainted with scrofula, or phthisis.

Perhaps there are no habits or acquired tendencies which are more surely transmitted than that of dipsomania or alcoholism; nor are there any which are more difficult to eradicate when inherited, or acquired in early life.

This diathesis, however, is not always repeated in form, but frequently passes into other abnormal conditions. Sometimes it manifests itself in some of the forms of insanity; and again in uncontrollable passions, or cruelty, or in idiocy, or again in a failure of moral character, or in epilepsy.

One of the most marked cases which have come under my own observation, occurred in a family resident in K——. The grandfather and father both died prematurely from the effects of alcohol, and one of the children, a lad of seven years, had such a passion for liquor, that he would swallow at once half a tumbler of wine or whiskey unmixed with water, and could never be near alcohol in any of its forms without begging for it. This child, at that age, could not enunciate clearly enough to be understood by those not familiar with him, and had been unable to learn letters, though much care had been expended to effect it.

Gall refers to a similar case, in which both the father and grandfather had prematurely died as drunkards, and a little grandson, exhibited strong tendencies for alcohol when aged only five years.[12]

“Charles X——, son of an eccentric and intemperate father, manifested instincts of great cruelty from infancy. He was sent at an early age to various schools, but was expelled from them all. Being forced to enlist in the army, he sold his uniform for drink, and only escaped a sentence of death on the testimony of physicians, who declared that he was the victim of an irresistible appetite. He was placed under restraint, and died of general paralysis.

“A man of an excellent family of laboring people was early addicted to drink, and died of chronic alcoholism, leaving seven children. The first two of these died at an early age, of convulsions. The third became insane at twenty-two, and died an idiot. The fourth, after various attempts at suicide, fell into the lowest grade of idiocy. The fifth, of passionate and misanthropic temper, broke off all relations with his family. His sister suffers from nervous disorder, which chiefly takes the form of hysteria, with intermittent attacks of insanity. The seventh, a very intelligent workman, but of nervous temperament, freely gives expression to the gloomiest forebodings as to his intellectual future.”[13]

Dr. Morel, after having an opportunity of studying the subject in a very large number of cases observed among the “gamins” of Paris, came to the conclusion, that the effects of alcohol were of the most terrible nature, especially when used in boyhood and early manhood, not alone on those using it, but on their descendants; and that it became manifest in “physical, moral, and mental degenerations.”Echeverria,[14] who has collected a large number of statistics on the subject, gives the following in reference to the histories of sixty-eight males and forty-seven females who had experienced alcoholism in some of its forms: The number of children born to these persons was four hundred and seventy-six: and of this total, twenty-three were still-born; one hundred and seven died from convulsions in infancy; thirty-seven died from other maladies; three committed suicide; ninety-six are epileptic; thirteen are congenital idiots; nineteen, maniacal or hypochondriacal; seven have general paralysis; five, locomotor ataxy; twenty-six, hysteria; twenty-three, paralysis; nine, chorea; seven, strabismus; three are deaf; and nineteen are scrofulous and crippled. Of these children, two hundred and five (205), or nearly fifty per cent., have exhibited drinking tendencies.

From the above statistics it appears that of all the nervous diatheses which may be inherited, there are none which are more invariable in their effects, or more surely disastrous to their unfortunate victims, than that of alcoholism.

In short, imperfection and abnormality of nerve function in its relation to mind, especially of intellect and character, of all shades and degrees, may be inherited as well as acquired; and this is equally true when the condition has not attained to that of actual disease, but simply a tendency toward it. And if such tendency should exist on both sides of the house, it becomes increased in the offspring in geometrical ratio, except in so far as it may become modified through the influence of counteracting qualities of character under the law of atavism.

The question now arises: By what measures, or through what influences, if any, can such proneness to nervous diatheses be avoided? It may be replied, that there are two channels through which partial relief may come; but that any substantial results may follow, it will become necessary that education concerning the laws of heredity shall become more general, and the importance of right conduct in relation to them impressed especially on the minds of young persons.

First.—Through the influence of that law of heredity by means of which there may occur an elimination of weaknesses and proclivities toward disease. This influence comes from the healthy side of parentage; for instance, in the case of parents, one of whom has physical or psychological tendencies toward disease, if the other has a healthy and vigorous constitution, and is endowed with mental qualities of an opposite character, these forces of the system may prove to be quite sufficient to affect or neutralize those which, on the other side of the house, lead toward disease, and the offspring may have an inheritance nearly, or quite, free from such influence.

This is not unfrequently witnessed in the case even of the strongest hereditary diseases, namely those of phthisis and insanity. The offspring of mothers with proclivities toward either of these diseases, in case the father is strong, may escape entirely or nearly so; this is very often true when the well parent has an unusual power of transmitting race-characteristics, and belongs to a family which has been noted for longevity during two or three generations.

In this hereditary influence there lies a power of incalculable value to the human race, a power conducing toward the elimination of morbid diatheses, which otherwise would go on increasing in almost geometrical ratio, until families, or even whole communities, would become diseased.

The tendencies toward health, under favorable circumstances, are greater than toward disease, and, therefore, there exists a probability that race-characteristics on the healthy side may prevail over those on the unhealthy side of the house, though this may not always be found to be true in actual experience.

Through this line of influence, and this only, can there exist any probability of diminishing the increase of inherited insanity. Governments and society encourage, and rightly so, the institution of the marriage relation; the family is the corner-stone of society, and on it are reared the fabrics of civilization and civil institutions. Probably from no other practice or custom does there ensue so large effects in the way of happiness, prosperity, morality, and well-being to the human race, as from that of marriage; but the conditions of a large part of the beneficent results of this institution, depend upon freedom from certain tendencies to disease. Communities and states are composed of units, and their strength and stability must depend upon that of the individuals composing them. Quite in the degree that disease or degenerations, physical or mental, exist in any community, in that measure prosperity and happiness are diminished; so that from the stand-point of political economy, even, it becomes of vast importance that the laws of hereditary influence should be more fully understood.

The instinct of love, however, is so powerful in the vast majority of the human race, that it overrides almost all other considerations. Persons do not stop to consider consequences to themselves, or to those who are to come after; they are borne on by the considerations of a present fancy or sentiment, and there is reason to fear that any legal enactments, or regulations, even, in the present state of knowledge on this subject, would not be worth the paper on which they might be inscribed.

Probably the only thing which can be done is to instruct the public, and make known, so far as possible, the influences of hereditary tendencies, publishing them in the higher text-books of schools, and in periodicals. It might be more clearly understood in reference to marriage, that a sentimental fancy or a choice founded on the existence of like characteristics, either mental or physical, not only often proves to be of little real value in after-life toward securing happiness, but on the other hand proves, too often, to be the source of vast misery to parents, their children, and the community in which they may live; that the highest consideration for the present and future should lead to careful examination as to inherited characteristics on both sides, and of a selection which may tend toward elimination, rather than an increase, of these. It might be more fully understood that, generally, characteristics of body and mind of different qualities, within certain degrees of limit, contribute toward securing a well-balanced and healthy system, and also toward a larger degree of happiness in domestic relations; that acquired diatheses, as well as those inherited, are transmitted to those who come after; that violations of the laws of healthy brain activity are almost sure to be punished in the persons of children, whether they have consisted in immoderate devotion to business or study, or in any of the physical indulgences. In this way some advance may be hoped for, in guiding toward that course in which lies the least danger.

The old adage, however, that “the fathers have eaten sour grapes, and the children’s teeth are set on edge,” was a truth well understood some thousands of years ago,—and yet the fathers go on indulging in sour grapes, because the great truth fails to have taught its lesson, and the heedlessness of youth requires line upon line, and precept upon precept, as well as, ofttimes, the sternest of discipline. The future will doubtless be, in a large degree, as in the past, but we may hope that when the laws of inheritance are more commonly known, when the learning of them becomes a part of the general education of the young, their influence will be more beneficent than at the present time.

Especially may we have reason to expect that such will prove to be the result in reference to those diatheses which are formed through the influence of alcohol and tobacco, or by the indulgence of the lower passions, but the elimination of insanity by these means can, at the most, be only partial.

The second measure by means of which the unfavorable influences of heredity may be modified in their subjects, is that of education.I confidently believe the day will come when the first question which will be asked concerning a child who is to commence an education, will be as to his or her inheritance; and after obtaining all possible information concerning this point, it will be a part of the teacher’s duty to study the physical and mental traits and tendencies of each child in the light of this information. The time will come when the importance of individuality in education will be so highly appreciated that it will be considered as essential in all recognized systems. Already there has been a beginning in this direction, in reference to certain classes of children. It is not many years since feeble-minded children were treated as most others now are, and were left to get any little education they might be able to, with all others. Gradually the importance of individual education for these weak-minded ones has dawned on the public mind; so that by systems now in use, many of these, otherwise almost utterly useless members of the community, have been trained to a degree of usefulness and self-support.

What has been done for this class should be done for all classes of persons whose inheritance has in any measure been of a morbid character. These pyschic neuroses group themselves into certain forms, often at an early age, and require special care and training from childhood, lest they develop into actual disease in later life. Among these may be mentioned the following:

For each of these classes of children special lines of education and management should be followed, and they should be of such a character as may tend to repress and correct tendencies of character which in the future will be almost certain to become morbid. The professional observations of most physicians who have large experience with diseases of the nervous system, will suggest the cases of patients who have become insane, and in whose inheritances and histories some of the above-named characters have been specially prominent in childhood.

Whatever, therefore, is to be done with a view to modify proclivities toward those morbid neuroses which result from hereditary influences, or have been acquired through the force of habit, must be accomplished mainly through the influence of education, reaching, in different channels, both parents and children.

CONSANGUINEOUS MARRIAGES.