Consanguineous Marriages in the American Population Part 5

[Footnote 55: Dugdale, op. cit., Chart II.]

Mr. Dugdale makes the following "tentative inductions." 1. Boys preponderate in the illegitimate lines. 2. Girls preponderate in the intermarried branches. 3. Lines of intermarriage between Jukes show a minimum of crime. 4. Pauperism preponderates in the consanguineous lines. 5. In the main, crime begins in progeny where Juke blood crosses X blood. (Anyone not descended from a Juke, is of "X blood").

6. The illegitimate lines have chiefly married into X.[56] The third and fourth inductions might indicate that a lowered vitality of the consanguineous lines changed a tendency toward crime into the less strenuous channel of pauperism, but I cannot find in Mr. Dugdale's charts any sufficient basis for the induction. It is true that the most distinctively pauper line is consanguineous, but it is less closely inbred than the "semi-successful" branch. As to the fifth induction, a close examination of the data shows clearly that in nearly every case where an X marriage occurred, it was with a person of a distinctly immoral or criminal type. Cousin marriage has also been frequent in the middle western counterpart of the Jukes, the "Tribe of Ishmael."[57]

[Footnote 56: Dugdale, op. cit., p. 16.]

[Footnote 57: McCulloch, _Tribe of Ishmael_.]

A more recent study of hereditary degeneracy is that of the "Zero Family" in Switzerland.[58] Here the first degenerate was the product of two successive consanguineous marriages, both with a branch tainted _with insanity_. In spite of his bad ancestry he lived to the age of 106 years. He married an Italian woman of questionable antecedents, and was the father of a large family. Three hundred and ten of his descendants are mentioned, of whom many are still young. Of these 310, 74 died in early childhood, 55 are or were vagabonds, 58 were weak-minded or idiotic and 23 were criminals. Fifty-two were of illegitimate birth. Although some are counted in more than one category, the record is appalling. In this family however, the marriages were nearly all with foreign women, and the effect of consanguinity was only the intensification of the neurosis in the first two generations.

[Footnote 58: Joerger, "Die Familie Zero." Reviewed by Gertrude C.

Davenport, in the _American Journal of Sociology_, Nov., 1907.]

Dr. Bemiss found that 300 or 7.7 per cent of the offspring of consanguineous marriages were subject to scrofula.[59] This is a disease which is almost universally recognized as hereditary, and which we should therefore expect to find intensified by double heredity. But 7.7 per cent is obviously too high; otherwise most of the scrofulous must be the offspring of marriages of kindred. About one per cent of the children of my own correspondence cases were reported as scrofulous. And while the United States Census reports but 3.9 per cent of the blind as the offspring of consanguineous marriages, the percentage of the blind from scrofula is 6.1.[60] The blind from scrofula of consanguineous parentage were 2.8 per cent of all the blind of consanguineous parentage, while all the blind from scrofula were 1.8 per cent of all the blind. Consanguinity, then, seems appreciably to intensify scrofula, but there is no indication that scrofula is ever caused by parental consanguinity.

[Footnote 59: Bemiss, see _Trans. of Am. Med. a.s.so._, vol. xi, 1858, p. 420.]

[Footnote 60: _The Blind and the Deaf._ Special Report of 12th Census, 1906.]

CHAPTER V

CONSANGUINITY AND MENTAL DEFECT

Idiocy, perhaps more than any other disease or defect, has long been connected in the popular mind with the marriage of cousins. This fact is not surprising when we consider that until very recent times idiots were looked upon with a kind of superst.i.tious awe, and the affliction was supposed to be a curse of G.o.d. For this reason, when idiocy did follow consanguineous marriage as it sometimes would, it was believed to be the fit punishment of some violation of divine law. Insanity also frequently has been attributed to consanguineous marriage, but not so frequently as idiocy, since its occurrence later in life is not so obviously connected with pre-natal conditions.

The terminology of mental and nervous disorders has been so loosely applied that some definition may be necessary. By the term "idiocy,"

is meant a condition of undeveloped mentality. Idiocy exists in various degrees, from the complete absence of intellectual faculties to a condition of mere irresponsibility in which the subject is capable of self-help, and sometimes of self-support under the careful guidance of other. Under the generic term "idiot" may be included the "complete idiot," the imbecile, the "feeble-minded" and the "simpleton," all of whom suffer in a greater or less degree from arrested mental development.

Insanity, on the other hand, is a disease which destroys or clouds an intellect which has once been developed. It is true that certain conditions of idiocy and imbecility do resemble that phase of insanity known as dementia--a reversion to the original mental state of childhood--in reality a form of second childhood. But the states are not identical, although one may lapse into the other. One is defect, the other disease; the imbecile in the former being the counterpart of the dement in the latter, just as the moral imbecile is the a.n.a.logue of the paranoiac.[61]

[Footnote 61: Barr, _Mental Defectives_, p. 18.]

Of the strong inheritability of idiocy there can be no doubt. Dr.

Martin W. Barr of the Pennsylvania Training School for Feeble Minded Children has published an etiological table embodying the results of a careful examination of 4050 cases of mental defect. Of these, 2651 or 65.45 per cent resulted from causes acting before birth, including 1030 or 25.43 per cent with a family history of idiocy and imbecility, and 529 more (13.06 per cent) with a family history of insanity, epilepsy and minor neuroses. Dr. Barr gives many instances ill.u.s.trating the heredity of imbecility, especially where both parents were imbeciles, and had imbecile relatives. One case in particular forcibly ill.u.s.trates the disastrous results of the marriage of such unfortunates. It is taken from the reports of the Connecticut Lunacy Commission:

In one instance, where a pauper female idiot lived in one town, the town authorities hired an idiot belonging to another town, and not then a pauper, to marry her, and the result has been that the town to which the male idiot belongs has for many years had to support the pair and the three idiot children.[62]

[Footnote 62: Ibid., p. 99.]

Neuroses may remain latent for a generation and reappear in the grandchildren of the person affected, or the latent tendency may never reappear unless some disturbing factor such as scarletina, meningitis or other acute disease attacks the weak spot. This possibility suggests that the influence of heredity may be vastly greater than the etiological tables would indicate. The apparent causes may be only agents which a.s.sist in developing the evil really engendered by an inheritance of imbecility.

It is not at all certain that there is any well marked boundary line between genius and some forms of imbecility. Many quite irresponsible idiots have marvelous verbal memories, and can repeat parrot-like, page after page of books of which they have no comprehension. Dr. Barr tells of cases of prodigies, musical, mathematical and mechanical, who except in their specialty were almost totally deficient mentally.[63]

Many of the world's most brilliant musicians, mathematicians and even military leaders have been men of one-sided mental development, whose ability in other lines was so slight that they were little better than imbeciles, and it is not at all surprising that their children are sometimes truly idiotic.

[Footnote 63: Barr, op. cit., p. 301 _et seq._]

The best writers of the present day no longer recognize consanguinity as a cause _per se_, of idiocy. The heredity of neuroses, however, is so strongly established that few would dispute the proposition that where the morbidity is inherited through both parents it appears more frequently and in a more marked degree than where one parent is entirely free from taint. This is what occurs when a consanguineous marriage takes place between descendants of a neurotic family. The percentage of idiotic children would then be somewhat higher from consanguineous marriages than from the average marriage purely through the action of the laws of heredity.

Dr. Barr finds 49 out of 4050 cases of idiocy or 1.21 per cent, in which there was a family history of consanguinity. This is little higher than the average frequency of first cousin marriage, and an a.n.a.lysis of 41 of these cases does not show one case that can be attributed to consanguinity alone. To quote: "Two were the result of incestuous connection--one of brother and sister, the other of father and daughter, and in the others there was an undoubted history, of grave neuroses."[64] "Beach and Shuttleworth find in the consideration of their 100 cases (out of 2,380 idiots), giving 4.2 per cent (of consanguineous parentage) that the bad effects are due rather to the intensification of bad heredity common to both parents."[65]

[Footnote 64: Barr, op. cit., p. 94.]

[Footnote 65: Ibid., p. 109.]

Dr. Arthur Mitch.e.l.l examined all idiots in nine counties of Scotland and found that 42 out of 519 or 8.1 per cent of whom the parentage was known, were children of first cousins.[66] Dr. Down found 46 out of 852 or 5.4 per cent to be children of first cousins.[67] Dr. Grabham of the Earlswood Idiot Asylum in Surrey, England, stated that 53 out of 1388 patients were the offspring of first cousins. The facts, he adds, were obtained from the parents and are "therefore tolerably trustworthy."[68] Other investigations give percentages as follows: Kerlin, 7; Rogers, 3.6; Brown, 3.5 and C.T. Wilbur, 0.3.[69]

[Footnote 66: Darwin, see _Jour. Stat. Soc._, p. 173.]

[Footnote 67: Huth, _Marriage of Near Kin_, pp. 210-211.]

[Footnote 68: Darwin, op. cit., p. 166.]

[Footnote 69: Barr, op. cit., p. 109.]

The earlier American writers, Drs. Howe and Bemiss, believed that consanguinity was a cause of idiocy. Dr. Howe inquired into the parentage of 359 idiots and found that in 17 families the parents were nearly related; in one of these cases there were 5 idiotic children; in 5 families there were 4 idiots each; in 3 families 3 each; in 2 families 2 each; and in 6 families i each. In all 17 families there were 95 children of whom 44 were idiots, 12 were scrofulous and puny, 1 was deaf, 1 dwarf--58 in low health or defective, and only 37 fairly healthy. These of course are selected cases and do not indicate at all, as Dr. Howe supposed, that consanguinity was the cause of the disasters. He adds that in each case one or both of the parents were either intemperate or scrofulous, and that there were also other predisposing causes.[70] Dr. Bemiss found that 7.8 per cent of his 3942 children of consanguineous marriages were idiots, while but 0.7 per cent of the children of non-consanguineous parentage were idiotic.[71] A more detailed examination reveals the fact that in a large number of these, one or both of the parents were mentally defective. For example, in a marriage of double cousins the wife was "feeble minded" and the six children were of inferior mentality. In a case of first-cousin marriage the wife became insane and two of the children were idiotic. In a case of the marriage of cousins, themselves the offspring of cousins the husband was a hypochondriac, and seven children idiotic. In another marriage of the same cla.s.s both parents were feeble-minded and the children idiotic. These are simply taken at random, and many others might be given. When we find also that in a majority of cases no report is given of the ancestry, it is very obvious that consanguinity alone could not have been the cause of any large proportion of the 308 cases of idiocy in the Bemiss report.

[Footnote 70: Barr, op. cit., p. iii.]

[Footnote 71: Bemiss, op. cit., p. 420.]

My own investigations show that out of 600 children of first cousin marriage (from correspondence) 26 or 4.3 per cent are mentally defective--10 are reported as "idiots," 13 as "weak-minded" and 3 as "imbeciles." In at least five of these cases there is evidence of bad heredity, in two others the father was intemperate and in two more causes acting after birth are mentioned.

The statistics of the insane and idiotic in Prussia presented by Mayet clearly indicate the large part which heredity plays in the production of mental disorders. Tables XX and XXI set forth the most important results of his work. Mayet considers a case hereditary if any near relative of the subject suffered from mental or nervous disorder, or was intemperate, suicidal, criminal or eccentric.[72]

[Footnote 72: Mayet, _Verwandtenehe and Statistik_, quoted by Feer, _Der Einfluss der Blutsverwandschaft der Eltern auf die Kinder_, p.

13.]

TABLE XX.

-------------------------------------------------- | No. of |Percentage | Cases. |hereditary.

-------------------------------------------------- 1. Simple Insanity |102,097 | 31.7 = 100 Consanguineous parentage | 664 | 69.0 = 218 Parents cousins | 595 | 68.1 = 215 Parents uncle and niece | 66 | 77.3 = 244 -------------------------------------------------- 2. Paralytic Insanity | 22,936 | 17.6 = 100 Consanguineous parentage | 95 | 45.3 = 257 Parents cousins | 87 | 44.8 = 255 Parents uncle and niece | 8 | 75.0 = 426 -------------------------------------------------- 3. Epileptic Insanity | 14,067 | 25.6 = 100 Consanguineous parentage | 79 | 53.2 = 208 Parents cousins | 70 | 50.0 = 195 Parents uncle and niece | 9 | 66.7 = 261 -------------------------------------------------- 4. Imbecility and Idiocy | 16,416 | 28.7 = 100 Consanguineous parentage | 237 | 43.0 = 150 Parents cousins | 211 | 43.1 = 150 Parents uncle and niece | 26 | 38.5 = 134 --------------------------------------------------

Table XXI gives the proportion of the mentally defective who are the offspring of consanguineous marriages. The term "cousin" in both these tables probably means first cousins. It will be remembered that Prussian statistics of consanguineous marriages are very imperfect, but that at least 6.5 in every thousand are consanguineous (first cousins or nearer).

TABLE XXI.[73]

_Parentage of Mental Defectives in Prussia._ ----------------------------------------------------- | Consan- | |Uncle and |guineous.|Cousins.| Niece.

----------------------------------------------------- 1. Insanity (simple) | 6.5[A] | 5.8[A]| .64[A]

Hereditary | 14.2 | 12.5 | 1.6 Not hereditary | 3.0 | 2.7 | .22 ----------------------------------------------------- 2. Paralytic Insanity | 4.1 | 3.8 | .35 Hereditary | 11.1 | 9.6 | 1.48 Not hereditary | 2.9 | 2.5 | .11 ----------------------------------------------------- 3. Epileptic Insanity | 5.6 | 4.9 | .64 Hereditary | 11.7 | 9.9 | 1.57 Not hereditary | 3.5 | 3.2 | .29 ----------------------------------------------------- 4. Idiocy and Imbecility| 14.4 | 12.8 | 1.58 Hereditary | 21.6 | 19.3 | 2.12 Not hereditary | 11.5 | 10.2 | 1.37 ----------------------------------------------------- [A] Per thousand.

[Footnote 73: Feer, op. cit., pp. 13-14.]

From these tables we may infer that consanguinity influences idiocy far more than it does insanity, but it is not entirely clear why the number of hereditary cases should be relatively smaller among the idiotic. Since insanity is more likely to have some more definitely a.s.signable cause than idiocy, we should expect the percentage due to heredity to be lower and consequently the influence of consanguinity less.

It is generally admitted that a tendency toward insanity is inheritable, and it seems probable that this tendency as well as other neuroses may be intensified through double heredity. A case in point can be found in the Shattuck genealogy.[74] For four generations in the S. family there is no indication of neurosis. The average number of children to a family had been eight, few children died young and all were prosperous farmers. But in 1719 J.S. married E.C. and their son Z.S. is thus described: "He was sometimes subject to depression of spirits; and some peculiar traits of character in a few branches of his family seem to have originated with him." He married A.C., a niece of his mother. They both lived to be over 80 and had ten children, of whom three were insane; only six married, and of these only two are known to have left surviving children. One of these a daughter, S.S., married E.S., a nephew of her father, and himself the offspring of a second cousin marriage within the S. blood. E.S. and S.S. had five children, all of whom married, and there is no further mention of insanity. We may suppose, then, that the C. stock was neurotic, and that a consanguineous marriage within that stock, although of the S.

surname, intensified the tendency into insanity, but with a further infusion of the normal S. blood the morbidity was eliminated. It is very evident that the heredity and not the consanguinity was the cause of these three cases of insanity.