Dysgenics

“ So far we have considered the causes of mental deficiency of hereditary origin. The causes in general may be grouped roughly under direct, which are due to heredity or disease, and indirect, due to sense defects and accidents. About 85 per cent, of the cases may be traced to conditions prior to birth, such as bad heredity, neurotic conditions, alcoholism and tuberculosis. Injuries at birth are at the present time rare and are responsible for not over 1 per cent., according to the best authoritories. ”

“ What we know of the endocrine factors in heredity leads us to suppose that it is the mating of one marked endocrine insufficiency with another that is often responsible for the inherited tendency to feeble-mindedness and insanity. The effect of the hormone system upon the vegetative apparatus may create the more obscure insanities and quasi-insanities. The direct action of the internal secretions upon the brain cells, producing a sort of hair trigger situation within them, may cause the explosive discharges from them which appear as overpowering impulses or uncontrollable conduct. ”

“ Teratological abnormities resemble neuropathies not only in their origin and the characteristics of their hereditability, but there can be found in their genesis, besides heredity, all the defective conditions of generation and gestation that have been charged, and justly, with the faculty of giving rise to disorders of the nervous system—emotions, shocks, defective food, alcoholism or any other intoxication, infections, etc. The greater frequency has been noticed of deformities among natural children in cases of conception during intoxication, disproportion in the age of progenitors, etc. ”

“ Early involvement of the germ is shown by the fact that the somatic malformations of the hereditary forms of insanity often involve the body elsewhere than in the [Pg 69] nervous axis. The stigmata of heredity—defective development of the uro-genital system, deformities of the face and skull, irregular development of the teeth, misshapen ears and limbs—owe their grave significance to this fact. Like deformities of the brain, these anomalies are also more marked and constant with the lower forms of the hereditarily based systematised perversions of the mind than the higher. ”

“ A few of the various defects which seem to be inherited as recessives when mated with normality are: susceptibility to cancer; chorea (St. Vitus’ dance) ; true dwarfism (all parts proportionately reduced) ; Alkaptonuria (urine darkens after passage) ; alcoholism and criminality, where based on mental deficiency; hereditary hysteria; multiple sclerosis (diffuse degeneration of nervous tissue) ; Friedreich’s disease (degeneration of upper part of the spinal cord) ; Merriere’s disease (dizziness and roaring in ears) ; [Pg 118] Thomsen’s disease (lack of muscular tone) ; hereditary ataxia ”

“ Our scientists in eugenics gather hosts of facts, showing by elaborate statistical figures that the family history of neurotics reveals stigmata of degeneration in the various members of the family. The eugenic inquirers do not stop for a moment to think over the fact that the same sort of evidence can be easily brought in the case of most people. In fact, the eugenists themselves, when inquiring into the pedigree of talent and genius, invariably find somewhere in the family some form of disease or degeneration. ”

“ Their common [Pg 10] characteristic is hereditary transmission under graver conditions than normal heredity. With certain exceptional instances of regeneration, the progeny of degenerates presents progressive degradation. This may reach such limits that humanity is preserved by its excess. It is not necessary, however, that the ultimate stage of degradation be reached before sterility occurs. Morel confines degeneracy to a pathologic type, criticising F. Heusinger [10] for applying the term degenerate to domestic animals which “throw back” to the wild or original type. ”

“ The treatment of all degenerates, and consequently their preservation from the evils that threaten them, ought to begin in their earliest infancy. First avoid exaggerating hereditary predisposition when serious neurosis has occurred in the parental line. Too often such a conclusion is adopted, and hope of recovery in the descendants is abandoned because one of the parents or the grandparents was affected with insanity by reason of organic disease of the brain. Preliminary examination of the neurotic needs to be made before one is enabled to judge as to the effects of heredity. ”

“ The first class demanding attention is that of those feeble-minded whose condition is due to heredity. There is reason to believe that at least two-thirds of the feeble-minded in the United States owe their condition directly to heredity, [80] and will transmit it to a large per cent of their descendants, if they have any. Feeble-minded persons from sound stock, whose arrested development is due to scarlet fever or some similar disease of childhood, or to accident, are of course not of direct concern to eugenists. ”

“ We should not, in fact, be surprised at finding that degenerates by heredity are not different from degenerates in consequence of disorders of nutrition in progenitors, since degeneration in general results from embryogenical troubles which are reduced, as a whole, to troubles of nutrition. The teratological theory of morbid heredity and of degeneration permits us to comprehend not only unlikeness in morbid heredity, but also the absence of heredity in diseases of the group presumed to be hereditary, but which might be more correctly called degenerative. ”

“ Now that many studies on the physiology and hygiene of reproduction of man have been made, and many investigations on degeneration have been conducted, we may face the problem of the betterment of the race, from a practical standpoint.
If the eugenic action cannot yet strive directly against hereditary transmission of anomalies, it can fight successfully against the causes of degeneration which act during the development of the individual. ”

“ Observation shows that the class known as degenerates is increasing much more rapidly than the general population and that their average duration of life has been lengthened. Diseases may be cured, but degeneracy, which is usually due to some inherited defect in the physical, mental or moral nature 94of the individual, is rarely amenable to curative treatment. It is only through applied eugenics that the vast volume of disease and degeneracy which flows through the channels of heredity can be prevented. ”

“ This community of origin, moreover, indicates that a higher vertebrate embryo contains in essence the organs and potentialities of lower vertebrates, and that under the influence of heredity or accidental defect an organ belonging to another species may develop, or an organ constant in a species may be lacking in an individual, without the necessity of explaining the immediate effects by distant atavism. Some anomalies found among degenerates recall types less elevated than man, and very distant from him, even his possible Lemurian precursor. ”

“ In man and in domesticated animals we find that individuals appear occasionally that are defective in one or another respect. Some of the defects are inherited. Rarely a new one appears that has not been seen before. But the majority of them are reappearances of characters that have been carried under the surface as recessive genes in the germ-plasm. Today we recognize that each of these modifications, if recessive, has first arisen as a mutational change in a single gene before it appeared on the surface as a character by the coming together of two such genes. ”

“ In determining the factor of heredity we must not be content with ascertaining the existence of psychoses in the ascendants, but must seek, by careful interrogation of various members of the family, for some of the hereditary equivalents, such as epilepsy, chorea, hysteria, neurasthenia, somnambulism, migraine, organic diseases of the central nervous system, criminal tendencies, eccentricities of character, drunkenness, etc., for these equivalents are interchangeable from one generation to another, and are simply evidence of instability of the nervous system. ”

“ Incapacity for bearing children can be acquired; it develops, however, abundantly on the grounds of a congenital predisposition.
4. In so far as the latter is the case, obstetrics contributes towards the diffusion of this incapacity.
[40]
5. The most serious obstacles to delivery are effected by deformities of the pelvis, in at least 90% of which heredity plays a part. In this connection, rickets, the predisposition to which is inherited, takes the foremost place.
6. German medical statistics make it appear probable that incapacity to bear children is on the increase. ”

“ The influence of nervous prostration in the father may be overcome by conditions in the mother tending to help development. As her share in the germ plasm is most emphatic, not only at the time of [Pg 347] the formation, but also during the entire development of the embryo, production of degeneracy will largely depend on her nutrition. The influence of healthy atavism is much more emphatically exerted through the female, albeit even in the male it may overcome the nervous exhaustion of the ancestor so far as reproduction of it is concerned. ”

“ We also detected a difference in the mode of inheritance of disease genes when classified according to essentiality. We find that disease lethal genes are more likely to demonstrate an autosomal dominant mode of inheritance. This reflects the tendency for disease to occur in the heterozygous state in these individuals, and that homozygosity for disease mutations would present a more severe phenotype causing lethality. Human disease mutations are not often nulls, and essentiality and disease can be considered on a spectrum with respect to mutant alleles. ”

“ Gene alleles with reduced function, called hypomorphic alleles, therefore can generate different phenotypes from those of null alleles. Although null or severe loss-of-function mutations in essential genes may indeed contribute to spontaneous miscarriages, hypomorphic mutations in the same genes can contribute to less severe abnormalities that are recognized as human disease. Therefore, the human orthologs of genes required for embryonic development in the mouse can cause disease in mutated forms through a variety of mechanisms. ”

“ Breeding Out Defects.—Even though recessive defects occur in a stock, there is the possibility of diluting out the imperfection in successive generations if care is taken always to marry into a stock wholly free from it. For example, a normal individual carrying a recessive defect will bear the abnormality in half of his or her germ-cells. This means that when such an individual marries a normal, non-carrier, half of their children will be wholly normal (AA) and half will be carriers; normal but of simplex constitution (Aa) . ”

“ The organisation of a morbid predisposition may be largely influenced by an accident accompanying conception or gestation. In some degenerates cannot be found a trace of hereditary defect. The fact cited explains how sensorial excitations or repeated and violent emotions in the mother during [Pg 57] pregnancy give rise to profound nutritive troubles in the fœtus, and especially in its nervous system. These congenitally degenerated beings (ab utero) can hardly be distinguished from those having direct heredity. ”

“ In short, the predisposition to disease may be hereditary or congenital. Hereditary transmission is, however, not inevitable, and most frequently it is due to very diverse conditions in the nutrition of the progenitors. Some authors have associated the idea of degeneration with that of heredity, and designate a whole category of disorders under the name of hereditary degenerations; but many persons who exhibit the characteristics of this category have not inherited them. ”

“ The authors of one study therefore conclude that essential genes are not human disease genes [9] , as mutations prevent viability. However, this assumption fails to consider the impact of alleles on gene function. Genes have been defined as essential due to the phenotype of mouse knockouts, which result from a deletion of the protein-coding region of the gene from the genome. These mouse mutants therefore are null alleles, and represent the phenotype caused by complete absence of functional protein. However, point mutations in these same genes do not necessarily fully remove protein function. ”

“ We do not know how widespread recessive genes are in the human germ-plasm. The fact that defective individuals appear in certain communities may be safely interpreted to mean that individuals bearing the same gene have at last come together. On the other hand, the absence of such individuals from the community, at large, may only mean that the chance of suitable combinations is small, and does not mean necessarily that the gene in question is confined to the community within which the defects have been recorded. ”

“ While severe mutant alleles that eliminate protein function represent the null state and confer lethality, hypomorphic alleles simply reduce protein function below an optimal level, resulting in a phenotype recognized as disease. In this manner, lethal genes can have mutations that only reduce protein function and therefore present as disease in the human population, allowing for inheritance of these more mild alleles in genetic diseases. ”