It may at once be admitted that, as has been claimed by a large number of observers, morbid heredity, especially in its graver forms, is much less frequent than at first would be expected. J. P. Gray, of Utica, New York, went so far as to claim that disease is never transmitted, but this is contradicted by his own hospital reports, which, to the day of his death, contained a table headed, "Statistics of hereditary transmission of the disease." It is true, however, that the descendants of a victim of morbidity or abnormality do not always exhibit the morbidity or abnormality of the ancestor. In some cases all apparent morbidity or abnormality is wanting. In other cases slighter abnormalities are to be detected. Here the observer is brought face to face with the operation of two general principles which are interdependent: the trans.m.u.tation of heredity and atavism, or "throwing back" as the cattle breeders call it.

Tennyson voices the general erroneous opinion of the always evil effects of atavism in his "Locksley Hall Sixty Years After":--

"Evolution ever climbing after some ideal good And Reversion ever dragging Evolution in the mud."

As Kiernan has shown, atavism at times tends to preserve the type, and offsets the influence of degeneracy. This element of atavism underlies not merely the production of the sound scions of degenerate stock, but also those in whom the degeneracy affects the earlier and not the later acquirements of the race. The contrast of the moral imbecile who is unable to acquire an idea of right, or the idiot of the lowest grade who can hardly be taught to keep himself clean, with the otherwise sound, sane, able victim of hereditary gout, is very great. Yet all the links of the chain connecting, in the same family, these contrasted types, can often be found. The law laid down as to absolute extinction through degeneracy by Morel and others can only be regarded as absolutely true when applied to a given type rather than the race as a whole. Indeed, environment may play a part in preserving a degenerate who would otherwise die out. Thus in societies at a certain stage of culture imbeciles, paupers, lunatics, and congenital criminals live at large and even propagate through legal marriage. The seemingly enormous increase of the defective cla.s.s which occurs in frontier communities when the cla.s.ses begin to be placed in public inst.i.tutions is an excellent ill.u.s.tration of this.

Manifestations of morbid heredity result not in inheritance of the whole defect but in disturbance of relations of structure and hence of function, producing, as Kiernan remarks, a const.i.tutional deficiency which takes the line of least resistance. The extent and direction of this line of least resistance depend on the amount of healthy atavism which separate organs and structures of the body preserve. The line of least resistance sometimes taken is excellently ill.u.s.trated in the occurrence of stigmata already pointed out in the case of epileptic guinea-pigs.

This unilateral predisposition (which, as Kiernan has shown, is due usually to heredity or intra-uterine causes) may be artificially produced. Kasparek[88] cut one sciatic nerve of a guinea-pig and (after all inflammatory symptoms had subsided) injected the opposite ear with cultures of pus microbes. He killed the animal after some days. The sound side was found free from suppuration, but immense abscesses existed on the side of the cut nerve. Such local predisposition was pointed out by Merrill[89] over forty years ago. This condition occurs, as Fere has shown,[90] in many systemic and infectious diseases which presents a localisation due to heredity, or determined by anterior morbid state of the nervous symptom. Sometimes these manifestations are limited to the side free from nervous trouble.

As a rule they attack the side which is the predominant seat of nervous symptoms. Fere points out that in chromatic iris asymmetry the iris (coloured part of the eye) is most coloured on the side most affected by arrest of development. Localisation of nervous trouble occurs on the side most affected by hare-lip. Heuse has observed the co-existence on the same side of congenital cataract and of deformities of the skull and chest.

Hernia is often an expression of hereditary defect (Le Double) taking the unilateral line of least resistance. t.e.s.t.i.c.l.e inflammations of microbic origin (venereal or otherwise) occur as a rule on the side where hernia is located in the groin. In one-sided malformations of ovary or t.e.s.t.i.c.l.e (decreased or increased in size, or changed in shape or location) microbe inflammation almost always occurs at the seat of the anomaly. This principle is ill.u.s.trated in the experiments of Dupuy.[91] Here, while as a rule, the scions of guinea-pigs (rendered epileptic by section of the sciatic nerve) were epileptics and had deficient toes, still in some epilepsy resulted without the toe anomaly, while still more rarely the toe anomaly was present without the epilepsy.

The same principle is shown by certain observations of Charin and Gley,[92] who for five years conducted experiments calculated to throw light on the influence on the offspring of parental reception of virus.

Either both male and female have been inoculated with the bacillus of blue pus or its toxins, or but one animal has been inoculated. The results have not been uniform. Most frequently there ensues sterility, abortion, or birth of progeny that die immediately. In rare instances the offspring survive; more rarely still are they healthy. Certain rabbits (born of these undeveloped animals) were provided with enormous epiphyses (ends of bones), the shafts of the bones being shortened. Two rabbits were born of a couple of which the male alone received inoculations of sterilised culture. Five rabbits were born of these two, of which two were normal, and a third (whose ears were rudimentary) died in a few days. In the remaining two the ears comprised only fragments with jagged upper edges.

The tails were but two centimetres long. The external orifice of the v.a.g.i.n.a (one rabbit was a male and the other a female) was oblique. One of the limbs (the hind in the male and the fore in the female) was much shorter than its fellow, the difference being four centimetres. The shortened limb ended in a kind of stump, there being no foot or toes.

These experiments ill.u.s.trate the transformation of heredity, that is the manifestations which show the line of least resistance that the morbid heredity has taken. As Moreau (de Tours) remarks,[93] "An incorrect conception of the law of heredity looks for identical phenomena in each succeeding generation. Some have refused to admit that mental faculties were subject to heredity, because the mental characters of the descendants were not precisely those of the progenitors. Each generation must copy the preceding. Father and son must present the spectacle of one being, having two births, and each time leading the same life, under the same conditions. But it is not in the heredity of functions, or of organic or intellectual facts that the application of the law of heredity must be sought, but at the very fountain-head of the organism, in its inmost const.i.tution. A family whose head is insane or epileptic does not of necessity consist of lunatics or epileptics, but the children may be idiotic, paralytic, or scrofulous. What the parents transmit to the children is not insanity, but a vicious const.i.tution which will manifest itself under various forms in epilepsy, hysteria, scrofula, rickets, &c.

This is what is to be understood by hereditary transmission."

The same position has been taken by Rush,[94] the pioneer American alienist; by Maudsley,[95] by Krafft-Ebing,[96] by Meynert, by Mercier, by Fere,[97] and others. Morel,[98] the chief accepted apostle of the doctrine of degeneracy, remarked, nearly at the same time as Moreau, that "heredity does not mean the very disorder of the parents transmitted to the children with the identical mental and physical symptoms observed in the progenitors, but means transmission of organic disposition from parents to children. Alienists have, perhaps, more frequent occasion than others for observing not merely this hereditary transmission, but likewise various transformations which occur in the descendants. They are aware that simple neuropathy (nervous tendency) of the parents may produce in the children an organic disposition resulting in mania or melancholia, nervous affections which in turn may produce more serious degeneracy and terminate in the idiocy or imbecility of those who form the last link in the chain of hereditary transmission."

What is true of the organism as a whole is true of the cells forming its organs. It should be remembered that while cell life is altruistic or subordinated to the life of the organ, through the law of economy of growth, recognised by Aristotle, and through it to the life of the organism as a whole, altruism is not complete enough to prevent entirely a struggle for existence on the part of the cells or the individual organs.

With rise in evolution this struggle decreases, to increase with the opposite procedure of degeneracy. From it results the phenomenon of arrested and excessive development.

As Dareste has shown (and the fact has been corroborated by Spitzka[99]), embryologists can imitate natural malformation of the nerve centres by artificial methods. By wounding the embryonic and vascular areas of the chick's germ with a cataract needle, malformations are induced, varying in intensity and character with the earliness of the injury and its precise extent. More delicate injuries produce less monstrous development. Partial varnishing or irregular heating of the egg-sh.e.l.l, in particular, results in anomalies comparable to microcephaly (little head) and cerebral asymmetry. This latter fact (showing the constancy of the injurious effect of so apparently slight an impression as the partial varnishing of a structure not connected with the embryo at all directly) suggests the line of research to be followed in determining the source of the maternal and other impressions acting on the germ. What delicate problems are to be solved in this connection may be inferred from the fact that eggs subjected to the vibration and shocks of a railroad journey are checked in development for several days, or permanently arrested. A more delicate molecular shock during the maturation of the ovum, during its fertilisation, or finally during embryonic stages of the more complex, and therefore more readily disturbed and distorted human germ, accounts for the disastrous effect of insanity, emotion, or other mental or physical shock of the parent on the offspring. The cause of the majority of cerebral deformities exists in the germ prior to the appearance of the separate organs of the body. Artificial deformities produce a.n.a.logous results because they imitate original germ defects, either by mechanical removal, or by some other interference with a special part of the germ.

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 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.

It is easy from these results to understand how far and how the nervous system has its part in the disorders of general development. It can be easily understood how the individuals who present most deformities are equally those who suffer from most decided disorders of the nervous system.

These morbid manifestations of heredity occur in certain categories, either local as to organs or structures, or affecting the body as a whole.

These categories Moreau (de Tours) lucidly sums up as: First, absence of conception; second, r.e.t.a.r.dation of conception; third, imperfect conception; fourth, incomplete products (monstrosities); fifth, products whose mental, moral, and physical const.i.tution is imperfect; sixth, products specially exposed to nervous disorders in order of frequency as follows--epilepsy, imbecility or idiocy, deaf-mutism, insanity, cerebral paralysis, and other cerebral disorders; seventh, lymphatic products; eighth, products which die in infancy in a greater proportion than sound infants under like conditions; ninth, products which, although they escape the stress of infancy, are less adapted than others to resist disease and death.

The explanation of these morbid manifestations lies in the very foundations of embryology. Bearing in mind the principles of individuation pointed out by Spencer, it is easily understood how reversal of this principle would produce greater and greater destruction of the complex functions, resultant on increased reproductive power of cells (whose environment is not suited to such reproductions) and thus lead to such a struggle for existence as to produce sterility (from interdestruction of the ovum cells, or the cells forming the spermatozoon). This condition is further increased by the operation of two biologic principles. The first relates to the cells or organs forming an organism. The second, as Von Baer has shown, deals with the relation of the organs to each other.

Vertebrate embryos of a common type, at their origin, a.s.sume successively a number of common forms before definitely differentiating. Dareste points out that supernumerary organs do exist in these common forms at one phase of embryonic life. This community of embryonic types and this last fact explain repet.i.tion of teratologic types or monstrosities in vertebrates.

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.

It is obvious from the principles already demonstrated that the secondary effects of infectious disorders and injuries are reproduced in various types in the offspring. The malformations of the limbs experimentally demonstrated to be due to ancestral infection by Charin and Gley, and to injury by Dupuy, noticeably occur in men. Moor has observed supernumerary fingers in an imbecile girl; her grandfather and one uncle are polydactylous and insane. F. S. Coolidge has had under observation a case which excellently depicts these deformities in men. Kiernan[100] reports the case of a man whose grandfather and father had been prophets of the Lord, as shown by the fact that on one side of the body they had six toes and six fingers, and the two sides of the body were unequal, the six-fingered one being smaller than the other. This father and grandfather were highly regarded in a secluded vale in Norway as religious teachers and for their power to cure disease by charm. The father had ten children, of whom three were born dead and six died in infancy. Kiernan's patient was the only survivor of this family. During boyhood he experienced various persecutions, some by unseen agencies, some on the part of the villagers, who towards the end of his father's life also persecuted the father. These persecutions seem to have been withdrawal by the peasants of their belief in the father's ability to charm sickness out of cattle, evidently due to growing popular intelligence. This was regarded by the father as the result of persecution by the devil, who was desirous of trying him as Job was tried. It was revealed to him that his son should likewise suffer persecution, which would also be the work of the devil.

The son heard unseen persons, who pointed him out in school as the son of the sham wizard. In consequence he was avoided by all his schoolmates except the members of one family who still retained their belief in the father's supernatural powers. Into this family the son married; then, pressed by his unseen persecutors, he came to the United States. Here he worked at his trade as a carpenter, and had no return of any persecutory delusions, although he still believed he was a prophet. On admission to the insane hospital, twenty years after his arrival in the United States, he was found to have such a decidedly asymmetrical body that suspicions of general hemiatrophy were excited, but the condition was found to be congenital. The hand and foot of the seemingly atrophic side had six fingers and toes. The man had been sent to the insane hospital in consequence of an altercation with a neighbour who was clearly in the wrong; but both being arrested, the patient's _amour propre_ was aroused and he declared his prophetship, which led to his trial and commitment as a lunatic. His wife, who applied for his discharge, was also a paranoiac.

They had had ten children, of whom three were still living at the ages of six, eight, and ten. Two of these were six-toed and six-fingered unilaterally, and one of them, a boy, had the peculiar general asymmetry of the father. The third child was seemingly normal.

The experimental results of Charin and Gley, on the degeneration produced in offspring by ancestral microbic infection, tend to show that not merely are the extremities affected, but in certain cases the whole organism, along lines laid down by Moreau's categories. This is demonstrated by study of the degeneracy stigmata of phthisical families. Alex. James, Ricochon,[101] C. E. Paddock,[102] and others have shown that (in addition to the ordinary stigmata) the biologic stigmata of degeneracy (such as plural and quickly repeated births) are frequent among phthisical families. The same phenomena often occur in families whose scions are attacked with diabetes, obesity, articular rheumatism, cancer and gout. De Giovanni[103] finds that particular nervous states exist in those predisposed to tuberculosis, whom he divides into erethists (restless), torpids, and energetics. There is a diminutive heart, whose right ventricle has comparatively exaggerated dimensions, while the arteries have lessened calibre.

A family ill.u.s.trating excellently the trans.m.u.tation of morbid heredity is one followed through five generations by Kiernan.[104] A farmer lived twenty miles distant from his nearest neighbour, whose only child he married. The daughter had led a lonely life till her courtship at the age of 28 by the farmer, then three years younger. The farmer married her for $300, after having impregnated her. He then found lead on his farm and went to a city. A stock-company bought his farm and launched him into the stock market, where he made money more as a cunning tool than an adventurer. He became a high liver, gouty and dyspeptic, and died with symptoms of gouty kidney at 70. The couple had five children. The eldest, a son, became a "Napoleon of Finance," but, inheriting his father's cunning, died wealthy and within the pale of the law. He married a society woman, the last scion of an old family. The second child, a daughter, was club-footed and early suffered from gouty tophi. She married a society man of old family who had cleft palate. The third child, a daughter, had congenital squint. She married a man who suffered from migraine of a periodical type. The fourth child, a daughter, was normal. She married a thirty-year-old active business man, in whom ataxia developed a year after marriage. The fifth child, a son, was ataxic at eighteen. The children of the "Napoleon of Finance" and the society woman were an imbecile son, a nymphomaniac, a hysteric, a female epileptic who had a double uterus, and a son who wrote verses and was a society man. The cleft-palated society man and club-footed woman had triplets born dead and a squinting, migrainous son who, left penniless by his parents, married his cousin the nymphomaniac daughter of the "Napoleon of Finance," after being detected in an intrigue with her. The migrainous man and squinting daughter of the farmer stockbroker had a s.e.xually inverted masculine daughter, a daughter subject to periodical bleeding at the nose irrespective of menstruation, as well as ch.o.r.ea during childhood, a normal daughter, a deaf-mute phthisical son, a daughter with cloacal formation of the perineum, an ameliac son, a cyclopian daughter (with one central eye) born dead, and, finally, a normal son. The s.e.xual invert married the versifier son of the "Napoleon of Finance." The progeny of the normal daughter of the farmer stockbroker and the ataxic husband were a dead-born, sarcomatous son, a gouty son, twin boys paralysed in infancy, twin girls normal, a normal son, and a son ataxic at fourteen. The progeny of the nymphomaniac daughter and her strabismic, migrainous cousin were a ne'er-do-well, a periodical lunatic, a dipsomaniac daughter who died of cancer of the stomach, deformed triplets who died at birth, an epileptic imbecile son, a hermaphrodite, a prost.i.tute, a double monster born dead, a normal daughter, and a paranoiac son. The ne'er-do-well married his nose-bleeding cousin. The gouty son of the farmer's normal daughter married the hysteric daughter of the "Napoleon of Finance." They had a son born with such general asymmetry as to seem hemiatrophic, a prost.i.tute, dead triplets, a male s.e.xual invert, a colour-blind daughter, and a normal son. The colour-blind daughter married the paranoiac grandson of the "Napoleon of Finance." The progeny of the s.e.xual invert and the versifier, who were soon divorced, were a daughter with periodical nymphomania, who had some artistic and literary ability, and a son who died of gastric cancer. The scions of the ne'er-do-well and his nose-bleeding cousin were a moral imbecile, a "bleeder," a stammering daughter who had an uvular deformity, a deaf-mute with undescended t.e.s.t.i.c.l.e, dead-born triplets, an infantile paralytic son, and dead-born quadruplets. The progeny of the paranoiac and his colour-blind cousin were an exophthalmic daughter, an epileptic with undescended t.e.s.t.i.c.l.e, a cleft-palated imbecile with a cloaca, dead-born quadruplets, an idiot boy, and a "bleeder."

Doutrebente reports the following family history: First generation: Father intelligent, became melancholic, and died insane. Mother nervous and emotional. Second generation: Ten children; three died in childhood, seven reach maturity as follows: Daughter A, melancholiac; daughter B, insane at twenty; daughter C, imbecile; daughter D, a suicide; son E, imbecile; son F, melancholic; son G, a melancholic. Third generation: A has ten children; five die in childhood, one is deformed, one has fits of insanity, one is eccentric and extravagant, two are intelligent and marry, but are childless. B leaves no issue. C has one child, a deformed imbecile. D has three children; one is an imbecile, one dies of apoplexy at twenty-three, and the third is an artist described as "extravagant." E has two children; one dies insane, the other disappears and is supposed to have committed suicide. F is childless. G has one child, who is imbecile.[105]

Strahan[106] gives a genealogy which shows very clearly the close kinship existing between the cancerous diathesis and other forms of const.i.tutional degeneration whose outward manifestations are infantile convulsions, suicide, epilepsy, insanity, lymphatism, and sterility. The father of this family died of stomach cancer at sixty. He had a brother who cut his throat at fifty-six; the mother, an apparently healthy woman, died of a fit, at the age of fifty-four. To this pair seven children were born: 1. A son who died of stomach cancer at fifty-eight. 2. A son who died in convulsions at thirteen weeks. 3, 4, and 5. Three daughters who died of phthisis, one at sixteen, the other two later in life, and after being married for many years; none left any issue. 6. A son who is epileptic, and has twice been confined in lunatic asylums; married, but no issue. 7.

A son who is sane, and enjoying fair health. Here the taint in the mother appears to have been slight; still, it was there, and while certainly preventing reversion, it doubtless deepened the degeneration of the father in the children. In the father's stock the taint was much deeper.

While it was exhibited as cancer in him, it took the form of suicidal impulse in his brother. In the children of this pair the disease of the father is transmitted to the eldest son; but can it be denied, Strahan asks, that the infantile convulsions, the liability to tubercular disease, the epilepsy, the insanity, and the marked sterility were but the varying evidences of the degenerate nature, inherited from a father who might have died earlier of some acute disease, taking the secret of his nature with him?

The value of the principle of atavism in off-setting degeneracy is nowhere better ill.u.s.trated than in the history of famous families of degenerates like those of the Binsw.a.n.gers, of "Margaret," of the Jukes, as well as those reported in France, Germany, Austria, Russia, and the Scandinavian countries. The Rougon-Macquart family of Zola (which had its actual prototype in the Kerangal family described by Aubry[107]) had, like these, several scions in whom former normality regained its power through atavism. Sometimes this atavism is not shown to any greater extent than a slight modification of the abnormality or morbidity.

Telegony, the so-called and much-debated heredity of influence, whereby the children of a second marriage resemble the first husband, may be explained by a biologic principle demonstrable in the lower animals, whereby conjugation not sufficient to fecundate ova is sufficient so to impress them that when finally fecundated they bear characteristics of the first conjugation. Its part in either normal or degenerate heredity is but slight. Some instances charged to it might be attributed to mental impression on the mother.

Luys[108] excellently sums up the whole question of heredity when he remarks: "Heredity governs all the phenomena of degeneracy with the same results and the same energy as it controls moral and physical resemblances in the offspring. The individual who comes into the world is not an isolated being separated from his kindred. He is one link in a long chain which is unrolled by time, and of which the first links are lost in the past. He is bound to those who follow him, and to the atavic influences which he possesses; he serves for their temporary resting-place, and he transmits them to his descendants. If he come from a race well endowed and well formed, he possesses the characters of organisation which his ancestors have given him. He is ready for the combat of life, and to pursue his way by his own virtues and energies. But inversely, if he spring from a stock which is already marked with an hereditary blemish, and in which the development of the nervous system is incomplete, he comes into existence with a badly balanced organisation; and his natural defects, existing as germs, and in a measure latent, are ready to be developed when some accidental cause arises to start them into activity."

CHAPTER IV

CONSANGUINEOUS AND NEUROTIC INTERMARRIAGE

Byron has sung[109] of the old popular belief in the advantages of cross-breeding, which arose originally in the practice of exogamy (marriage outside the tribe), or, more often, outside those having the same totem, or coat-of-arms. In all probability casual observation of deformities after intermarriage enforced the prohibition which arose after the killing of female children had led to exogamy. Totemic relationship was often far from being consanguineous. The idea of incest is, as Byron's stanza denotes, of religious origin rather than innate.[110] Its criminal nature is often removed by priestly dispensation in Latin countries. From this practice sprang the medical, theologic, and legal notions to which D.

H. Tuke[111] thus refers: "The danger arising from marriages of consanguinity has been insisted upon from time to time by medical writers, and has been recognised by ecclesiastical authority, civil law, and by popular feeling. As regards ecclesiastical and civil law, it would be more correct to say that the marriage of those very nearly related has been forbidden on other grounds than that of the alleged danger to mental health. At the same time the justice of such laws receives support if medical observation leads to the conclusion that consanguineous marriages tend to generate idiocy and insanity."

The biologic evidence from the experiments of Maupas on parthenogenesis, elsewhere cited, is seemingly supported by the results of animals breeding in-and-in. The evidence advanced against such marriages seems at first sight exceedingly strong from a biologic standpoint in man.

Rilliet[112] cites cases tending to show that consanguineous marriages, in themselves pernicious, tend with certainty to lower vital force. The effects he divides into two categories; those which relate to the parents, under which head are:--

_a._ Failure of conception.

_b._ r.e.t.a.r.dation of conception.

_c._ Imperfect conception.

Those which relate to the progeny:--

_a._ Imperfections of various kinds.

_b._ Monstrosities.

_c._ Imperfect physical and mental organisation.

_d._ Tendency to diseases of the nervous system, such as epilepsy, imbecility, idiocy, deaf-mutism, paralysis, and various cerebral affections.

_e._ Tendency to strumous diseases.

_f._ Tending to die young.

_g._ Tendency to succ.u.mb to disease which others would easily resist.

C. H. S. Davis,[113] of Meriden, Connecticut, states that intermarriages in families lead to a degeneration that manifests itself in deaf-mutism, albinism, and idiocy. Isaac Ray[114] is of the opinion that consanguineous marriages repeated through successive generations account for the numerous instances of insanity and idiocy occurring in quiet rural populations of New England, far from the excitements of city life, which are generally supposed to be more productive of mental unsoundness.

S. M. Bemiss,[115] of New Orleans, Louisiana, giving a report of the condition of the offspring of 580 intermarriages of first cousins, gathered mostly by medical men from nearly every State in the Union, says: 2,778 children were born of these cousins, of whom 793 were defective, 117 deaf and dumb, 63 blind, 231 idiotic, 24 insane, 44 epileptic, 189 scrofulous, 53 deformed, and 637 died early.