The Etiology of Mongolism
- Author:
Leslie Ray Marston, M.A.
Greenville College, Greenville, Illinois
Few types of mental deficiency are more interesting than the Mongolian, thus designated because of its striking resemblance to the ethnic type whose name it bears?a resemblance due largely to the peculiar oriental slant of the eyes so universally a characteristic of the Mongolian imbecile. While the Chinese physiognomy, totogether with other physical anomalies as well as characteristic mental traits, contributes to the interest in the type, no aspect of Mongolism is more interesting than its etiology, concerning which little is definitely known.
Down seems to have been the first to describe the type, 1886.1 He ascribed to tuberculosis the cause of Mongolism. Tredgold2 frequently discovered a tubercular taint in the histories of the cases he studied. Shuttleworth3 formerly believed this disease the most important factor in producing Mongolism, but later discredited this explanation, since tubercular heredity is quite characteristic of all types of imbeciles. Barr4 found a phthisical history in all but one fourth of the cases he observed.
Goddard5 cites four cases involving possible alcoholic heredity, but the evidence is far from adequate to establish alcoholism as the causative factor.
Tredgold6 notes that in nearly all cases neuropathic heredity can be traced. Shuttleworth7 attaches significance to neurotic tendencies in families in which Mongolism appears, and estimates that a neurotic taint is present in fifty per cent of cases. Goddard, however, while admitting that nervous disturbances are often found in such families, fails to find evidence warranting the conclusion that neuropathic heredity is peculiarly accountable for the occurrence of the condition.
Congenital syphilis has been advanced by some as the prime etiological factor. Sutherland is cited by Tredgold as having favored this explanation. Out of twenty-five cases he found eleven which he declared were unquestionably syphilitic. A more recent writer like1 According to McClelland and Ruh, “Syphilis as an Etiologic Factor in Mongolian Imbecility,” Jr. Amer. Med. Assoc., Vol. 68, No. 10, March 10, 1917. 2 Tredgold. Mental Deficiency, p. 183. 3 “Mongolian Imbecility.” Brit. Med. Jr., 1911, Vol. 2, pp. 661 ff. 4 Barr, “Mental Defectives,” p. 83. 6 Goddard, Feeble-mindedness, p. 454. 6 Tredgold, Mental Deficiency. 7 Shuttleworth, “Mongolian Imbecility,” Brit. Med. Jr., 1911, Vol. 2. wise inclines to this view, basing his argument upon the results of modern tests for syphilis,8 but McClelland and Ruh9 carefully studied thirteen Mongolians and obtained no positive Wasserman reactions, nor were they able to discover a syphilitic history in any of the cases. Tredgold early differed with Sutherland on the question of syphilis as an etiological factor since he found no preponderance of the disease among twenty cases.10 Shuttleworth and Potts11 tell of eight cases given the Wasserman Test, not one of which yielded a positive reaction. Hjorth, in a study of twenty-one cases, found no evidence whatever of syphilis.12
The confusion at this point may be due to faulty technique in diagnosing syphilis, or to error in diagnosing Mongolism. Cases of congenital syphilis, we are told, sometimes closely resemble Mongolian imbeciles both in physical features and in mental traits. According to Pardee,13 a positive Wasserman in a case of Mongolism seems to be a coincidence. The same authority asserts that the brains of Mongolians fail to reveal the characteristic pathological marks of syphilis. Goddard’s experience discredits the congenital syphilis explanation, and he suggests that were syphilis the cause, Mongolism would be far more prevalent than it is.14
Since Mongolism resembles in some respects the condition known as Cretinism, which is due to mal-functioning of the thyroid, a similar glandular disturbance suggests itself as the cause of the former, but, according to Tredgold, post-mortem dissections reveal no abnormalities of glandular structure. The Vineland Laboratory has found an abnormally high sugar tolerance pathogonomic of Mongolism, suggesting a defect in the ductless gland system,15 but experiments conducted at Vineland and reported by Goddard, in which Mongolians were subjected to treatment with various glandular extracts, failed to produce significant results. On the other hand, thyroid treatment of Cretinism is attended by phenomenal physical and mental improvement.
8 Stevens, in Jr. Amer. Med. Assoc., May 15, 1915; April 29, 1916. # “Syphilis as an Etiologic Factor in Mongolian Imbecility,” Jr. Amer. Med. Assoc., March 10, 1817. 10 Tredgold, Mental Deficiency, p. 182 f. 11 Mentally Deficient Children, p. 122 (1916 edition). 12 Cited by Tredgold (p. 183) from Journal of Mental Science, Jan. 1907. 13 Pardee, “Two Cases of Mongolian Idiocy in the Same Family,” Jr. of Amer. Med. Assoc., vol. 74, Jan. 10, 1920. 14 In Jr. Amer. Med. Assoc., vol. 68, p. 1057, April 7, 1917. 16 The Research Department. Publications of Vineland Training School, No. 1, May 1914.
An interesting fact, and one suggestive of a partial explanation of Mongolism, is the relatively high incidence of the defect among the younger children of large families?a fact mentioned by numerous authorities. According to Wallin,16 Mongolians “usually come from later pregnancies of parents between forty and fifty of good hereditarj’’ qualities.” Very frequently the Mongolian is the last born. Of the twenty-one cases reported by Hjorth (referred to above) eleven were the last born in their respective families. Goddard found among 294 cases, 151 or fifty-two per cent who were the last born in families of more than one.17 Hunter reports 136 cases, sixteen of which were the first born, fifty-four intermediate, and sixty-six the last born in families averaging 7.3 children. He observes that when the child is the first born, the mother is usually old for a prima para; when the child is born near the beginning of the child-bearing period, the mother is often subsequently sterile; when born toward the close of the period, it is likely to be the last.18 When the child is not the last born, it is often found that during pregnancy the mother underwent a severe illness. Quoting Tredgold: “Many of the patients were the later born of a large family, often numbering as many as ten or twelve, and where this was not the case there was usually a state of severe physical prostration of the mother during the gestation period.” Goddard makes a similar observation. This tendency of Mongolism to appear in children born during the later part of the mother’s reproductive period, or following a severe nervous or physical shock to the mother during pregnancy, suggests that the condition may be due to an impoverished or exhausted reproductive power, induced by any one of a large number of factors, or a combination of factors, but generally indicating a waning of the procreative function in later years which prevents the development of the foetus to the point normally attained at parturition. The view that Mongolism is due to arrested or interrupted foetal development is supported by Hunter19 on the ground that the Mongolian is but the four or five months’ foetus multiplied by thirty or forty?the slant eyes, stubby hands, narrow skull base, flattened occiput, and other traits of Mongolism being likewise characteristic 16 Wallin, The Mental Health of the School Child, p. 349. 17 Goddard, Feeble-mindedness, p. 451. 18 In Kelynack’s Defective Children, Chap. 3. 19 Ibid.
of the foetus. Shuttleworth20 in his second edition (1900) calls Mongolians “unfinished” children. In his fourth edition (1916), he refers to his earlier characterization of the type and adds: Dr. Thomson has, however, improved upon our description by the use of the term “ill-finished,” pointing out that, although something goes wrong in their growth in very early intra-uterine life, probably in their second month, yet their later development goes on continuously, though badly.
Goddard notes that Mongolians are strikingly similar in their mental development, usually attaining a mental level of four or five years, very rarely exceeding seven or falling below four. This fact, together with their striking physical similarity, leads him to conclude that there may be a definite point in foetal development when arrest takes place.21 Perhaps a more accurate explanation?that suggested by Thomson as cited by Shuttleworth?would state that the impoverished vitality of the mother’s reproductive powers only suffices to bring the foetus to a certain stage of development before parturition. This development may be continuous from conception, though retarded because of constitutional uterine debilitation (as in advanced age), or development may be normal to a certain point, when, because of serious illness or nervous shock, progress is interrupted and subsequent development is so slow that at delivery the foetus has reached that stage which characterizes the child as a Mongolian. From data at hand the age of the mother seems to be the most important factor in determining Mongolism. Goddard submits figures for 294 cases showing the number of Mongolians born in each year of the mother’s life. His figures are reproduced in Table I. Concerning these data Goddard remarks: “As to whether the proportion of children born at any given age of parents is greater for Mongolians, we can not say from this table… . The number of children (Mongolian) born when the mother is forty is much higher than at any other age. This may or may not be significant.”22 The writer has attempted to answer the question raised by Goddard: “Is the proportion of children born at any given age of the mother greater for Mongolians?” Goddard’s 294 cases of Mongolism have been grouped into periods of mother-age for purposes of comparison with the mother-ages of 3,697 unselected births for one year in an 20 Mentally Deficient Children, p. 54 (1900 edition). 21 Feeble-mindedness; p. 453. See also Jelliffe and White: Modem Treatment of Nervous and Mental Diseases, Chap. 4. 22 Goddard, Feeble-mindedness, p. 420.
Table I Age of Mother No. Born Age of Mother No. Born Ageof Mother No. Born Age of Mother No. Born Age of Mother No. Born 16 17 18 19 20 21 22 2 1 5 2 6 10 6 23 24 25 26 27 28 29 5 3 8 10 9 7 6 30 31 32 33 34 35 36 6 4 9 8 15 12 37 38 39 40 41 42 43 14 15 15 39 21 14 8 44 45 46 47 50 52 55 10 2 4 1 1 1
eastern city,23 and with the mother-ages of 143 births of all types of feeble-mindedness excluding Mongolians, selected at random from the inmates of Lincoln State School, Lincoln, 111. Table II gives the distributions and percentages in each five-year period.
Table II 19 and younger 20-24 25-29 30-34 35-39 40 and older All births 3,697 cases.. No. % 268 7.2 1,206 32.6 1,135 30.7 677 18.3 332 9 79 2.1 Feeble-minded. 143 cases No. % 12 8.3 39 27.3 42 29.4 32 22.4 11 7.7 7 4.9 Mongolians… 295 cases No. % 10 3.4 30 10.2 40 13.6 35 11.8 71 24.1 109 36,9
The accompanying chart is a graphic representation of the facts exhibited in Table II. Note the close correlation between the motherages of “all-births” and “defectives,” and with these contrast the tendency of Mongolians to be born at the higher mother-ages. Whereas but 2.1 per cent of all births and 4.9 per cent of all defective births occur when the mother is forty or older, 36.9 per cent of Mongolian births occur during this period. Although the number of cases upon which the curve for the unselected feeble-minded is based is small, the evidence is incontrovertible?the proportion of children born when the mother is forty or above is much greater for Mongolians than for either normal births or unselected defectives. Another striking feature of Mongolism is its higher incidence 23 Data from Infant Mortality?Results of a Field Study in Brockton, Mass. Mary V. Dampsey, U. S. Dept. of Labor, Children’s Bureau, Infant Mortality Series No. 8.
among better families. Goddard, in a study of the classes for defective children in the New York City schools, found by far the greater number of Mongolians in those schools located in the better sections of the city.24 So marked is this tendency, and so seldom are other defectives found in the family in which a Mongolian appears, that a Mongolian has been termed a “certificate of good blood,” but this certificate is not always valid. There are a few cases on record of more than one Mongolian in a family. Pardee gives an account of two Mongolian brothers.25 Shuttleworth cites a case of twins, one of which was normal and the other a Mongolian, and another instance observed by Hjorth in which both twins were Mongolians.26 Other cases are on record, but they are relatively rare.
Conclusion: The weight of evidence points to an explanation of Mongolism on the basis of arrested foetal development through uterine exhaustion due to any one of a number of factors, or a combination of factors. This study indicates that a significant factor in inducing this state of uterine exhaustion which results in Mongolism in the offspring is advanced age in the mother.
Incidence of births according to mother-age, showing proportionately more Mongolian births than normal or unselected feeble-minded births in the latter ages.
24 Goddard, Feeble-mindedness, pp. 450 and 453. 25 “Two Cases of Mongolian Idiocy in the Same Family,” Jr. Amer. Med. Assoc., Vol. 74, Jan. 10, 1920. 24 “Mongolian Imbecility”?Brit. Med. Jr., 1911, Vol. 2. Chart I /9ur*. ZQ-Z4ywj** /”?// bi’tths Un SiC.lec.t~ed fee hie,?’* dec/ A7 ongol’drts
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