In a paper by Weeks (The Inheritance of Epilepsy), in part an extension of an earlier joint paper by Davenport and Weeks, is recorded among others a study of twenty-seven fraternities in which both parents were either epileptic or feeble-minded. Of the 28 progeny, 19 lived long enough to reveal their mental state. Of these 3 were feeble-minded, 8 epileptic and 8, from parents who developed epilepsy late in life, were what Doctor Weeks terms “tainted.” In 15 fraternities in which one parent was epileptic and the other feeble-minded he found there had been 81 conceptions. Of these 7 were too young to classify and 19 had died before fourteen years of age. Of the remaining 55, 28 were epileptic, 26 feeble-minded, and 1 insane. Again, in 9 families in which the parents were both feeble-minded, of the 38 surviving offspring who were old enough to classify, 7 were epileptic, 29 feeble-minded, and 2 drunkards. In 5 families where one parent was insane and the other epileptic or feeble-minded, 5 children died before the age of fourteen, the condition of 2 was unknown, 2 were epileptic, 4 feeble-minded, 1 insane, 8 tainted, and 7 seemingly normal. Regarding the latter Doctor Weeks says they came from two families where in one case the father’s insanity seemed to be traumatic and in the other alcoholic.
In a few cases where the defect in one parent has apparently been of a type different from the defect of the other parent a “normal” child was produced. That is, presumably each parent carried normality in the trait defective in the other so that the child became simplex with reference to each defect. Davenport points out that not infrequently two deaf-mutes whose defects are due to different causes may have normal children.
In general, however, the reasonable expectation is that where two feeble-minded individuals marry, a very common occurrence, the children will all show mental deficiency. A mating between a feeble-minded person and one of perfectly normal stock will apparently result in normal children although they will be carriers. There is some evidence, however, that such carriers may occasionally show “taints” of abnormality in the form of migraine (nervous sick headache), alcoholism, queerness, violent temper, etc. Thus according to the studies of Doctor Weeks, “In 50 matings where at least one parent is migrainous, there were 350 conceptions, of which number enough is known of 212 to classify 55, or 26 per cent., as epileptic; 12, or 6 per cent., as feeble-minded, with the others tainted or normal. In the 131 matings where at least one parent is alcoholic, there were 845 conceptions. Of the 494 classified, 151, or 31 per cent., were epileptic; 54, or 11 per cent., feeble-minded, with the balance tainted or normal.” Marriage between two carriers will cause the defect to reappear in active form in approximately 25 per cent. of the offspring and 50 per cent. will continue to be carriers.
Many Apparently Normal People Really Carriers of Neuropathic Defects.—There is considerable evidence that many apparently normal individuals of our average population are in reality carriers of some form of neuropathic defect, some authorities placing the proportion provisionally at over thirty per cent. This being true, then it is easy to explain the apparently unaccountable appearance of epilepsy, feeble-mindedness, or similar defects among the children of what pass for normal stocks. The probabilities are that in many cases it means simply that the parents of the defective children have been carriers.
As to the contention that in preventing the propagation of the feeble-minded we may be depriving the world of geniuses, Doctor Goddard remarks: “It is a significant fact that in our three hundred family histories totaling 11,389 individuals not a single genius has been found. Not only are there no geniuses but the fact can not be too strongly emphasized that even the people who are considered normal ... are not as a rule people of average intelligence....” However, between insanity and genius he finds more kindred spirit.
Tests for Mental Deficiency.—As to tests for mental deficiency, the one commonly meted out to victims in the every-day world is the social-economic one of survival in the competitions of life. The mentally deficient fail. Although often unrecognized as feeble-minded they drift through life social and economical derelicts who have to be supported by the community.
Of laboratory tests many have been devised. While all yet leave much to be desired, still through their application the majority of mental defectives can be detected. Fairly accurate standards of normality have been established from which the relative degree of “backwardness” can be determined. We have just awakened to the importance of detecting defectives early in life, hence many of our tests have been planned with reference to children. They are based not so much on training or conscious learning as on fundamental processes which develop at certain ages in children. Another impetus toward securing adequate criteria of mental deficiency has been the crying need of having some easily applied standard for detecting the very large numbers of defective immigrants who are continually seeking to enter the United States.
Most of the methods consist of “performance” tests which are planned to test the powers of perception, concentration, application, ingenuity and education of the subject. Previous environment, education and the difficulties under which the subject may be laboring at the time of the test must, of course, be taken into account. It is particularly difficult to get adequate tests for the immigrant which will enable one to distinguish between ignorance, stupidity, fear and temporary psychic depression on the one hand, and congenital mental deficiency on the other.
Perhaps the most successful single set of tests for mental deficiency is that known as the Binet-Simon Scale. From an examination of large numbers of French school children Binet constructed a scale of tests of increasing complexity accurately graded to age and previous training of the average normal child. In the Binet-Simon system tests are given for each age from three years to thirteen. When a child successfully passes the tests for his age he is classed as normal. If he succeeds only in tests which normally are those given for a child a year younger then he is backward to the extent of one year. Similarly he may show by these graded tests that he is backward to the extent of two years, three years and so on. If a child is more than three years backward according to the test he is regarded as mentally defective. Various corrections and adjustments of the original scale have been worked out to allow for unevenness in mental development. On the whole the scheme works out satisfactorily when applied by one skilled in its use. The attitude of the examiner, however, is of so great importance that the tests are of less value in the hand of inexperienced workers. A revision of the scale to adapt it better to American children has recently been made by Doctor Goddard.[10] Besides the Binet-Simon tests various performance tests, standardized for children of different ages, such as Seguin’s form board, Healy’s pictorial completion test, Fernald’s construction puzzle, the Rossolimo test, De Sanctis test, etc., are used by different investigators. Questions designed to reveal moral tone are also employed. Doctor Howard A. Knox, assistant surgeon United States Public Health Service, in a recent article[11] gives an interesting account of the tests applied to determine the exact mentality of immigrants entering the United States together with a brief review of various tests. A full account and discussion of the various tests for the mentally subnormal will be found in a recent publication by Doctor William Healy,[12] director of the Juvenile Psychopathic Institute, Chicago.
The Backward Child in School.—It is only in recent times that we have come to realize the seriousness of the problem which the backward child presents in our schools. It is of the utmost importance to discover early in school life which of the backward children owe their condition to adenoids, defective sight or hearing, poor nutrition, imperfect circulation, or other remediable defects, and which are the victims of innate mental deficiency. The treatment of the individual must be very different in the two cases. In the one the condition can be cured by proper manipulations or other treatments; in the other it can only be ameliorated. All school children who are two or three years below grade should be rigidly inspected by the medical examiner.