We may consider next the hereditary history of some forms of nervous defect, the exact nature of the causes of which can be less definitely stated than in all of the preceding instances of defect. Fig. 20 gives a brief history of the heredity of Huntington's ch.o.r.ea--a form of insanity which here resulted in the death of all but one of the affected persons in the first four generations; the fifth generation is the present and is incomplete. Although the matings were with normals in every case, yet in four of the eight marriages all of the offspring were affected. From one affected male 23 affected persons descended in four generations and their multiplication is still going on. There can be no doubt as to the unfitness of marriage into such a family.

[Ill.u.s.tration: FIG. 18.--Family history showing a form of night blindness. Character of matings incompletely known.

(Data from Bordley.)]

A very complete family history showing deaf-mutism is given in Fig.

21. It cannot be said that in every case here the defect is innate, i. e., hereditary, and it is not known that the cause of the defect was the same in every family concerned, for deaf-mutism may result from several different causes. In most cases in this history, however, the defect behaves like a Mendelian dominant. In certain other cases it is clearly known to follow the Mendelian formula. Such pedigrees as this show how dangerous it is to marry into a family in which this defect exists.

[Ill.u.s.tration: FIG. 19.--Family history showing a form of night blindness. (Condensed form of Nettleship's data.)]

G.o.ddard has recently published several family histories showing feeble-mindedness. One of the most significant of these--significant both socially and eugenically--is summarized here in Fig. 22. Of this G.o.ddard writes: "Here we have a feeble-minded woman [IV, 3] who has had three husbands (including one 'who was not her husband'), and the result has been nothing but feeble-minded children. The story may be told as follows:

"This woman was a handsome girl, apparently having inherited some refinement from her mother, although her father was a feeble-minded, alcoholic brute. Somewhere about the age of seventeen or eighteen she went out to do housework in a family in one of the towns of this State [New Jersey]. She soon became the mother of an illegitimate child. It was born in an almshouse to which she fled after she had been discharged from the home where she had been at work. After this, charitably disposed people tried to do what they could for her, giving her a home for herself and her child in return for the work which she could do. However, she soon appeared in the same condition. An effort was then made to discover the father of this second child, and when he was found to be a drunken, feeble-minded epileptic living in the neighborhood, in order to save the legitimacy of the child, her friends [_sic_] saw to it that a marriage ceremony took place. Later another feeble-minded child was born to them. Then the whole family secured a home with an unmarried farmer in the neighborhood. They lived there together until another child was forthcoming which the husband refused to own. When, finally, the farmer acknowledged this child to be his, the same good friends [_sic_] interfered, went into the courts and procured a divorce from the husband, and had the woman married to the father of the expected fourth child. This proved to be feeble-minded, and they have had four other feeble-minded children, making eight in all, born of this woman. There have also been one child stillborn and one miscarriage.

"As will be seen from the chart, this woman had four feeble-minded brothers and sisters [IV, 6, 10, 15, 16]. These are all married and have children. The older of the two sisters had a child by her own father, when she was thirteen years old. The child died at about six years of age. This woman has since married. The two brothers have each at least one child of whose mental condition nothing is known. The other sister married a feeble-minded man and had three children. Two of these are feeble-minded and the other died in infancy. There were six other brothers and sisters that died in infancy."

[Ill.u.s.tration: FIG. 20.--Family history showing Huntington's ch.o.r.ea. Last generation incomplete. (Data from Hamilton.)]

The paternal ancestry of this unfortunate woman is hardly less interesting, as may be seen from the diagram. All told, this family history, as far as it is known, includes 59 persons; the mental character of 12 of these is unknown; 10 died in infancy or before their characteristics were known; of the remaining 37, 30 were feeble-minded.

[Ill.u.s.tration: FIG. 21.--Family history showing deaf-mutism.

(From "Treasury of Human Inheritance.")]

Turning now to defects of other kinds, an interesting history is ill.u.s.trated in Fig. 23. Here a single individual fatally affected with angio-neurotic oedema gave rise, in four completed generations, to 113 persons, 43 of whom were affected. In 11 this disease was the direct cause of death. The Mendelian character of the heredity here can be neither a.s.serted nor denied. In generations II-V matings between normal and affected gave 42 affected and 35 unaffected offspring.

Fig. 24 gives a brief family history showing pulmonary tuberculosis.

In the history given susceptibility to this disease behaves as a Mendelian dominant. We cannot as yet say whether this is or is not a general rule. In describing the heredity of diseases primarily due to infection, one or two important cautions must be observed. Of course the source of the infection cannot be "hereditary," and apparently it is only in comparatively few instances that infection occurs during fetal life. To some infections certain persons are susceptible, others are not; some when susceptible are capable of developing immunity, others are not. When an infection is of such character and prevalence that practically all persons in approximately similar environments of a given character are infected, susceptibility or the power of developing immunity will determine whether or not an individual will exhibit the disease caused by the infective agent. Practically all persons living in the denser communities are infected with tuberculosis; those who are susceptible and incapable of developing immunity succ.u.mb, the insusceptible and those developing immunity do not. These conditions are heritable; but in speaking of the heredity of such a disease as tuberculosis it should be clear that the heredity concerned is really that of susceptibility and the power of developing immunity. Yet the person who is really susceptible can, by taking sufficient precaution, escape serious infection, and thus the result for that person would be the same as if he were insusceptible, but his offspring would have to take similar precautions if they were to escape the disease.

[Ill.u.s.tration: FIG. 22. Family history showing feeble-mindedness. Data from G.o.ddard. _A_, alcoholic; _d.i._, died in infancy; _E_, epileptic; _ill._, illegitimate; _in._, incest; *, same individual as _III_, 6; _n.m._, not married; _S_, s.e.xual pervert; _T_, tuberculous.]

[Ill.u.s.tration: FIG. 23.--Family history showing angio-neurotic oedema. (From "Treasury of Human Inheritance.")]

[Ill.u.s.tration: FIG. 24.--Family history showing tuberculosis.

(Data from Klebs, after Whetham in "Treasury of Human Inheritance.")]

We cannot speak of heredity in connection with diseases to which all are susceptible and incapable of developing immunity. The presence or absence of such a disease is determined solely by the presence or absence of infection. Many physical and mental defects result from infection as the primary cause. If the infection is one to which all exposed are susceptible and incapable of developing immunity we cannot speak of the defect as in any way hereditary; if the infection is one to which some are susceptible, others not, to which some can develop immunity, others cannot, then we may speak of the defect as hereditary. Thus certain forms of blindness or insanity are due primarily to gonorrheal or syphilitic infection, insusceptibility to which is rare or unknown. Such defects cannot be considered as affording evidence of heredity though they reappear in successive generations.

In general the subject of the heredity of immunity and susceptibility forms one of the most important eugenic aspects of this whole subject.

In a few cases it is known that immunity or insusceptibility to specific forms of infection is a unit character which follows Mendelian laws in heredity. It can be added to races or subtracted from them and pure bred immune races built up. So far this has not been demonstrated for man. There is some circ.u.mstantial evidence that immunity to specific forms of infection has been a great, although hitherto neglected, factor in man's evolution, and even in the history of his civilization and conquest. It is at once obvious that here is a great field for the common labor of the students of heredity and of medicine and of Eugenics.

Fig. 25 ill.u.s.trates a family history of infertility. This is apparently hereditary, but before that could be a.s.serted definitely to be so here or in any similar case, we should know that the infertility were not the result of an infection to which immunity is rare or unknown. That infertility is really hereditary in this instance is indicated, first, by the fact that the person marked A later, by a second marriage into fertile stock, had a large family, and second, by the fact that the individual B and his child by marriage into fertile stocks produced in the last generation again a large family and so saved this whole family from extinction.

[Ill.u.s.tration: FIG. 25.--Family history showing infertility.

(From Whetham.)]

Before leaving the subject of the heredity of the kinds of traits we have been using as ill.u.s.trations, we should add just a word. It is often objected that one cannot properly speak of the heredity of such general things as "insanity" or "deaf-mutism" or "blindness" or "heart disease," because each of these includes a great variety of specific forms of these disorders which cannot strictly, medically, be compared. But the student of heredity replies that when he speaks of the heredity of insanity or heart disease, that is often just what he means. He means that often no particular form of these defects is necessarily strictly heritable as such, but that in a family there may be a general instability of nervous system or circulatory system, which may take any one of several possible specific forms, the form actually appearing depending upon particular conditions which are frequently environmental and beyond determination. In some cases specific forms of disorder are actually heritable as such.

Such an inclusive thing as "ability" may depend upon many different specific conditions. Yet there are families in which persons of exceptional ability are unusually frequent. The fact that persons of ability are more frequent in certain families than in the general population of the same social cla.s.s and with about the same opportunity for the demonstration of inherent ability, gives evidence of its heredity, although we may not be able to summarize the facts under any particular law but must adhere to their statistical expression.

[Ill.u.s.tration: FIG. 26.--Family history showing ability.

(From Whetham.)]

Figs. 26 and 27 ill.u.s.trate two such pedigrees of ability. In each of these histories there is also a line of "unsoundness" the descent of which it is interesting to trace. It is instructive to compare here the progeny of matings of different kinds. In generation IV of Fig.

26, the 9th and 10th persons are brother and sister. The sister was of considerable ability and married into a family of ability, producing 8 offspring, 5 of whom were able. The brother was a "normal" person and married a similar individual, producing 10 "normal" children. It would be interesting to know the details regarding these two large families of cousins. Another interesting comparison is found in this pedigree.

The four able brothers in generation III, coming from a stock of demonstrated ability, married women of undemonstrated ability and all told had 13 children (IV) of whom only 3 showed ability and all of these were in a single family. In this family of the fourth brother two of the able members married into able families, and among their 11 children (second and fifth families in generation V) 8 showed ability; the third able member of this family, however, married as her uncles had, a person not known as able, and none of their 6 children showed unusual ability (sixth family in generation V). Fig. 27 affords other ill.u.s.trations of this same kind. Thus in generation III the 5th and 7th persons are able cousins of able parentage. The former married a normal and 1 of their 5 children showed ability; the latter married a person of ability and 5 of their 8 children showed ability. In both pedigrees the "careers" of those in the last generation are partly incomplete.

[Ill.u.s.tration: FIG. 27.--Family history showing ability.

Paternal ancestry of family shown in Fig. 26. (From Whetham.)]

In discussing pedigrees of ability it should be borne in mind that the larger proportion of able males as compared with females is hardly significant for the study of heredity; it may merely reflect the unfortunate fact that women have not had the same opportunity to demonstrate inherent ability as have men; or it may evidence the still more unfortunate fact that the distinguished achievements of able women have not been socially recognized as such and recorded as they have been for the other s.e.x.

Fig. 28 gives an interesting, though abbreviated, pedigree of three very able and well-known families. In this history only persons whose ability is in science are marked as able. Charles Darwin is the third individual in the third generation. His cousin, Francis Galton, the founder of Eugenics, is the next to the last person in the same generation.

Many similar cases of the unusual frequency of individuals of musical or religious ability in certain families have been published by Galton and are well known. "As long as ability marries ability, a large proportion of able offspring is a certainty, and ability is a more valuable heirloom in a family than mere material wealth, which, moreover, will follow ability sooner or later."

We might contrast with such families as have been recorded in the three preceding figures some well-known families at the other pole of society. As an interesting example we have the family described by Poellmann. This was established by two daughters of a woman drunkard who in five or six generations produced all told 834 descendants. The histories of 709 of these are known. Of the 709, 107 were of illegitimate birth; 64 were inmates of almshouses; 162 were professional beggars; 164 were prost.i.tutes and 17 procurers; 76 had served sentences in prison aggregating 116 years; 7 were condemned for murder. This family is still a fertile one and the cost to the State, i. e., the taxpayers, already a million and a quarter dollars, is still increasing.

[Ill.u.s.tration: FIG. 28.--History (condensed and incomplete) of three markedly able families. (From Whetham.)]

One of the best known families of this type is the so-called "Jukes"

family of New York State so carefully investigated by Dugdale. This family is traced from the five daughters of a lazy and irresponsible fisherman born in 1720. In five generations this family numbered about 1,200 persons, including nearly 200 who married into it. The histories of 540 of these are well known and about 500 more are partly known.

This family history was easier to follow than are some others because there was very little marriage with the foreign-born--"a distinctively American family." Of these 1,200 idle, ignorant, lewd, vicious, pauper, diseased, imbecile, insane, and criminal specimens of humanity, about 300 died in infancy. Of the remaining 900, 310 were professional paupers in almshouses a total of 2,300 years (at whose expense?); 440 were physically wrecked by their own diseased wickedness; more than half of the women were prost.i.tutes; 130 were convicted criminals; 60 were habitual thieves; 7 were murderers. Not one had even a common school education. Only 20 learned a trade, and 10 of these learned it in State prison! They have cost the State over a million and a quarter dollars, and the cost is still going on. Who pays this bill? What right had an intelligent and humane society to allow these poor unfortunates to be born into the kind of lives they had to lead, not by choice but by the disadvantage of birth? Darwin wrote long ago "... except in the case of man himself, hardly anyone is so ignorant as to allow his worst animals to breed."

[Ill.u.s.tration: FIG. 29.--History of _Die Familie Zero_.

(Condensed from Jorger's data, partly after Davenport.)]

Probably the most complete family history of this kind ever worked out is that of the "Familie Zero"--a Swiss family whose pedigree has been recently unraveled in a splendid manner by Jorger. In the seventeenth century this family divided into three lines; two of these have ever since remained valued and highly respected families, while the third has descended to the depths. This third line was established by a man who was himself the result of two generations of intermarriage, the second tainted with insanity. He was of roving disposition, and in the Valla Fontana found an Italian vagrant wife of vicious character.

Their son inherited fully his parental traits and himself married a member of a German vagabond family--Marcus, known to this day as a vagabond family. This marriage sealed the fate of their hundreds of descendants. This pair had seven children, all characterized by vagabondage, thievery, drunkenness, mental and physical defect, and immorality. Their history for the three succeeding generations is incompletely summarized in Fig. 29. In 1905, 190 members of this family were known to be living, and probably many living are unknown on account of illegitimate birth.

In 1861 a sympathetic and charitable priest attempted to save from their obvious fate many of these "Zero" children and others who resided in and near his village, by placing them in industrious and respectable families to be reared under more favorable auspices. The attempt failed utterly, for every one of the "Zero" children either ran away or was enticed away by his relatives.

The blame for such an atrocity as this family or the Jukes does not rest with these persons themselves; it must be placed squarely upon the shoulders and consciences of the intelligent members of society who have permitted these predetermined degenerates to be brought into the world, and who are to-day taking no broadly sympathetic view of their treatment by exercising preventive measures. _Laissez faire?_

At the risk of easing the conscience, let us finally return to the other side of society and look at a summarized statement of the Edwards Family given by Boies and drawn from Winship's account of the descendants of Jonathan Edwards. "1,394 of his descendants were identified in 1900, of whom 295 were college graduates; 13 presidents of our greatest colleges; 65 professors in colleges, besides many princ.i.p.als of other important educational inst.i.tutions; 60 physicians, many of whom were eminent; 100 and more clergymen, missionaries, or theological professors; 75 were officers in the army and navy; 60 prominent authors and writers, by whom 135 books of merit were written and published and 18 important periodicals edited; 33 American States and several foreign countries, and 92 American cities and many foreign cities, have profited by the beneficent influence of their eminent activity; 100 and more were lawyers, of whom one was our most eminent professor of law; 30 were judges; 80 held public office, of whom one was Vice President of the United States; 3 were United States Senators; several were governors, members of Congress, framers of State const.i.tutions, mayors of cities, and ministers to foreign courts; one was president of the Pacific Mail Steamship Company; 15 railroads, many banks, insurance companies, and large industrial enterprises have been indebted to their management. Almost if not every department of social progress and of the public weal has felt the impulse of this healthy and long-lived family. It is not known that any one of them was ever convicted of crime."

The serious consideration of bodies of facts like those contained in some of these pedigrees leads every thoughtful and sympathetic, every humanely minded, human being to ask--What _can_ we _do_ about it? The display of such conditions stimulates us to measures of relief. It is greatly to be regretted that the honest desire to do good often leads to the performance of ill-considered or unconsidered acts which may result in positive injury to the const.i.tution of society, or at any rate at best merely in the amelioration of the immediate situation without reference to ultimate profit or penalty, or to the necessity for interminable amelioration. Such relief leaves out of account the fact that modifications are not heritable--not permanent, practically without effect in the long run. "Good intentions" have a certain well-known value as paving material, but not as building material.

The science of Eugenics includes not only the study of the data in this field, but further the formulation of definite courses of procedure; but it insists that these be based upon scientific principles and not upon emotional states. Philanthropic relief has become a serious business--is becoming a science. Eugenics is a science and it aims to put the human race upon such a level that the need for philanthropic relief will be less and continually less. We shall then be able to devote more of the resources of our time and money and energy to the production of permanent results. The Eugenist pleads in this work for more sympathetic consideration of the problems of relief--for a sympathy which is wider, which transcends the individual person and reaches the social group, even the nation or race. For just as a society is something more than the sum of its individual parts when taken separately, so the consideration of all the component individuals of a society taken separately and by themselves, results in something less than social consideration. Again "Charity refers to the individual; Statesmanship to the nation; Eugenics cares for both."

What, then, does the Eugenist propose to do? What is the eugenic program? Eugenics is not an academic matter--not an armchair science.

It is intensely practical--so very practical, indeed, that the Eugenist hesitates to make many suggestions of a definite nature looking directly and immediately toward specific action. Something must precede action. The Eugenist has been ridiculed as one responsible for the absurd schemes proposed in his name, perhaps seriously, by the unscientific but well-intentioned sympathizer. Many persons have been led to object to what they believed to be a eugenic program which is not a eugenic program at all. Thus the willingness of some to offer adverse criticism of the subject and its aims has grown largely out of a common misconception of the matter and has led Galton to say, "As in most other cases of novel views, the wrongheadedness of objectors to Eugenics has been curious." As a scientist the Eugenist realizes clearly and fully that his new science is in a very early stage of its development. It is just entering upon what are the first stages in the history of any science, namely, the periods of the formulation of elementary ideas and the collection of facts. There are certain groups of facts, however, of glaring significance and undoubted meaning, and upon these as a basis the Eugenist already has a few, a very few, concrete suggestions for eugenic practice. In conclusion, then, we may outline tentatively and briefly a conservative eugenic program somewhat as follows:

First of all there must be an extensive collection of exact data--of the facts regarding all the varied aspects of racial history and evolution. These facts must be collected with great care and under the strictest scientific conditions. In this matter particularly must we "desert verbal discussion for statistical facts." Figures can't lie, but liars can figure. What we need first of all is the acc.u.mulation of ma.s.ses of cold, hard facts, uncolored by any point of view, untinged by any propaganda: facts regarding the net fertility of all cla.s.ses; facts regarding the racial effects of all sorts of environmental and occupational conditions; facts regarding variability and variation in the race; facts regarding human heredity of normal and pathological conditions, of physical and psychical traits. We have merely scratched the surface of the great ma.s.ses of such data to be had for the looking. As Davenport has recently put it in his valuable essay on "Eugenics"--

"While the acquisition of new data is desirable, much can be done by studying the extant records of inst.i.tutions. The amount of such data is enormous. They lie hidden in records of our numerous charity organizations, our 42 inst.i.tutions for the feeble-minded, our 115 schools and homes for the deaf and blind, our 350 hospitals for the insane, our 1,200 refuge homes, our 1,300 prisons, our 1,500 hospitals and our 2,500 almshouses. Our great insurance companies and our college gymnasiums have tens of thousands of records of the characters of human blood lines. These records should be studied, their hereditary data sifted out and ... placed in their proper relations"

that we may learn of "the great strains of human protoplasm that are coursing through the country." Thus shall we learn "not only the method of heredity of human characteristics but we shall identify those lines which supply our families of great men: ... We shall also learn whence come our 300,000 insane and feeble-minded, our 160,000 blind or deaf, the 2,000,000 that are annually cared for by our hospitals and Homes, our 80,000 prisoners and the thousands of criminals that are not in prison, and our 100,000 paupers in almshouses and out.

"This three or four per cent of our population is a fearful drag on our civilization. Shall we as an intelligent people, proud of our control of nature in other respects, do nothing but vote more taxes or be satisfied with the great gifts and bequests that philanthropists have made for the support of the delinquent, defective, and dependent cla.s.ses? Shall we not rather take the steps that scientific study dictates as necessary to dry up the springs that feed the torrent of defective and degenerate protoplasm?