CHAPTER III. Heredity and Atavism

HEREDITY AND ATAVISM

Heredity, like other biologic factors, starts with the cell. As elsewhere pointed out, reproduction is first unicellular in type and involves an expenditure of nutritive force antagonistic to the growth of the cell. As Geddes remarks, no one can dispute that the nutritive, vegetative, or self-regarding processes within the plant or animal are as opposed to the reproductive, multiplying, species-regarding processes, as income to expenditure or as building up to breaking down. But within the ordinary nutritive or vegetative functions of the body there is necessarily a continuous antithesis between two tissue-changing sets of processes, constructive and destructive metabolism. The contrast between these two processes is seen throughout nature, whether in the alternating phases of cell-life or in the great antithesis of growth and reproduction.

The starfish, deprived of an arm, replaces this by a fresh growth; crabs can renew the great claws which they have lost in fighting; even as high up as the lizard the loss of a leg or a tail can be made good. In a great variety of cases a kind of physiological forgiveness is shown in the reparation of even serious injuries. Now this "regeneration," as it is called, is a process of reproduction. By continuous growth the cells of a persistent stump are able to reproduce the entire number. A sponge, a hydra or a sea-anemone may be cut into pieces with the result that each fragment grows into a new organism. The same is done with many plants; and though the division is artificial the result shows how very far from unique is the process spoken of as reproduction, which is but more or less discontinuous growth. This is well shown in the evolution onward insensibly from cases of continuous budding, as in sponge or rosebush, to discontinuous budding in hydra zoophyte and tiger-lily, where the offspring vegetatively produced are sooner or later set free.

The enormous expenditure of force required for unicellular reproduction is lessened by conjugation with another cell through satisfaction of cell hunger; and this, by making two cells do the work of one, lessens the amount of nutritive force expended by each. Evolution in fertilisation has the following steps:--

I. Formation of plasmodia. II. Multiple conjugation. III. Conjugation of the two similar cells. IV. Union of incipiently dimorphic (different) cells. V. Fertilisation of differentiated sex elements.

As Maupas has shown, by the time conjugation of two similar cells is reached, the paranucleus in both is incipiently hermaphroditic. The impelling force leading to conjugation is, as Rolph has shown, cell hunger. Conjugation, he remarks, is a necessity for satisfaction, a gnawing hunger which drives the animal to engulf its neighbour, to isophagy (self-eating). The process of conjugation is only a special form of nutrition which occurs because of a reduction of the nutritive income or an increase of the nutritive needs. It is an "isophagy" which occurs in place of "heterophagy" (eating of others). "The less nutritive, and therefore smaller, hungrier, and more mobile organism is the male, the more nutritive and usually relatively more quiescent organism the female. Therefore, too, is it that the small starving male seeks out the large, well-nourished female for purpose of conjugation, to which the latter, the larger and better nourished, is on its own motive less inclined." The unicellular type of reproduction long remains after sex differentiation has occurred and assumes the form of parthenogenesis (virgin generation). The phenomena of this demonstrate that the female element is the highest in evolution. Spitzka has shown that the ovum possesses an inherent activity independently of fructification. How far this may extend in the direction of more mature development is shown by what is known about parthenogenesis. This is the development of living beings without a father. Bees, some butterflies, ants and wasps notoriously multiply their kind without sexual congress. As a rule the parthenogenetic offspring are themselves incapable of further procreating their kind. But to this there are remarkable exceptions. The aphides multiply for many generations without the intervention of a male. Weigenbergh has shown that the silk-moth can be propagated as long as the male element is permitted to act at every fourth generation. The Artemsia salina, a minute crustacean living in saline springs, reproduces its kind for years without a male being present, males being produced at definite intervals only (Von Siebold). Among the vertebrata parthenogenetic development has also been observed, though rarely reaching maturity. Thus, segmentation occurs in unfertilised ova of the chicken (Oellacher), of the fish (Burnett and Agassiz), and of frogs (Moquia-Tanden). Spitzka has seen a blastoderm form in unfertilised ova of the toad-fish (Batrachus tau). Hensen isolated the oviducts of a rabbit, thus rendering the admission of semen impossible, while the ova, discharged at heat, were compelled to remain in these oviducts. Three years later he killed the animal and found the ova had developed into twisted, club-shaped, hollow sacs. The development in the female ovary (also, though very rarely, in the male testicle and parotid gland, which show such a remarkable metastatic sympathy in mumps), of dermoid cysts (containing bones recognisable as maxillaries with teeth, hair, and skin, rudimentary bowel, gland, and brain traces), even in undoubted virgins, proves that even the human ovum is capable of parthenogenetic development. While such development, so far as known to science, is always abortive, and while, as Washington Irving remarks, the ingenious maiden who to-day would attribute conception to any other cause than sexual congress would find it difficult to overcome the prejudice of scientists, yet embryology, while declaring immaculate generation improbable, does not pronounce it impossible. A worker bee may be an offspring of an unimpregnated queen bee. What is a regular occurrence in one class of animals is sometimes observed as an exceptional one in another class. If the startling and apparently miraculous nature of a virgin generation of a living child be regarded as the sole objection to receiving such a fact, its defender might urge that the virgin generation of a dermoid cyst with all the traces, however aborted, of vertebrate organisation, is only a shade less startling and miraculous.

This power of parthenogenesis, however, cannot continue indefinitely without extinction. This has been shown by the careful experiments of Maupas, who had observed 215 generations of an infusorian without sexual union. He found that then the family became extinct. Powers of nutrition, division, and conjugation with unrelated forms come to a standstill. The first symptom of this senile degeneration is decrease in size, which may go on till the individuals only measure a quarter of their normal proportions. Various internal structures then follow suit "until at last formless abortions occur, incapable of living and reproducing themselves." The nuclear changes are no less momentous. The important paranucleus is fatally sterile. The larger nucleus may also become affected, "the chromatin gradually disappears altogether." Physiologically, too, the organisms become manifestly weaker, though there is excessive sexual excitation. Such senile decay of the individuals and of the isolated family inevitably ends in death. Sexual union in those infusorians, dangerous perhaps for the individual life, a loss of time so far as immediate multiplication is concerned, is, in a new sense, necessary for the species. The life runs in cycles of a sexual division which are strictly limited. Conjugation with unrelated forms must occur else the whole life ebbs. Without it the protozoa, which some have called "immortal," die a natural death. Conjugation is the necessary condition of their eternal youth and immortality.

Starting from this standpoint the relative functions of the two sexes in heredity are apparent. The original function of reproduction, that of cell division, is the part of the female. The male in the lower instances simply supplies the female with nutriment. Thus in certain plants there is nothing but a subtle osmosis between the sexes. This is also the case with some of the lower infusoria. With a rise in evolution protoplasm becomes differentiated. At the outset of the subject of heredity it is evident, therefore, that the female furnishes the type which is best capable of development when properly nourished by a highly developed male. To deficiencies in both particulars are due defects and variations in the offspring. As the product of fructification is longest under the nutritive control of the female, her influence is most emphatic in either redeeming defects or producing them. Heredity, according to Ribot, Spitzka, Féré, and others, is divisible into direct heredity, indirect heredity, and, more dubiously, telegony. Direct heredity consists in the transmission of paternal and maternal qualities to the children. This form of heredity has two aspects: (1) The child takes after father and mother equally as regards both physical and moral characters, a case strictly speaking of very rare occurrence; or (2) the child, while taking after both parents, more especially resembles one of them. Here again distinction must be made between two cases. The first of these is when the heredity takes place in the same sex from father to son, from mother to daughter. The other which occurs more frequently, is where heredity occurs between different sexes--from father to daughter or from mother to son. Reversional heredity or atavism consists in the reproduction in the descendants of the moral or physical qualities of their ancestors. It occurs frequently between grandfather and grandson, as well as between grandmother and granddaughter. Collateral or indirect heredity, which is of rarer occurrence than the foregoing, and is simply a form of atavism, subsists, as indicated by the name, between individuals and their ancestors in the indirect line--uncle, or grand-uncle and nephew, aunt and niece. Finally (3) there is telegony, or the heredity of influence, very rare from the physiological point of view, which consists in reproduction in the children by a second marriage of some peculiarity belonging to a former spouse.

In dealing with heredity the position of Weismann and others, that acquired characters cannot be inherited, needs a short examination. In his later work Weismann has practically abandoned the essential basis of his position by admitting that maternal nutrition may play a part in determining variation. He now asserts that the origin of a variation is equally independent of selection and amphimixis, and is due to the constant occurrence of slight inequalities of nutrition in the germ plasm. As acquired characters affecting the constitution of the parents are certain to affect the nutrition of the germ plasm, it is therefore obvious, according to Weismann's admission, that acquired characters or their consequences will be inherited. This is an emphatic though concealed abandonment of the central position of Weismann.

One of the stock arguments of the Weismann school is drawn from results of the Jewish rite of circumcision. While the operation is not calculated to make a profound impression on the constitution, and furthermore, as being performed on the male, less likely to affect the race, still the alleged non-inheritance of its results is much over-estimated. William Wolf, of Baltimore, Maryland, who has circumcised six hundred Jewish children, finds on careful examination, that 2 per cent. were born partially circumcised and 6 per cent. were born with a short prepuce. P. C. Remondino, of Los Angeles, California, has seen a large number of cases of absence of the prepuce which proved to be hereditary. After a confinement his attention was once called to the child by the nurse, who thought it was deformed. The nurse was astonished at the size and appearance of the glans penis. On examination the prepuce was found to be completely absent. On inquiry, the father and another son, born more than twenty years previously (comprising every male member of the family), were found to have been born with the glands fully exposed. He has seen a French family similarly affected.

Similar, but much stronger, results have been obtained by me through the courtesy of the Reverend Drs. S. Bauer, M. A. Cohen, and B. Gordon, all of Chicago. Dr. Bauer, who has been seventeen years in the practice of the religious rite of circumcision, has circumcised 3,400 boys and has found preputial absence in about 3-1/2 per cent. of the cases. Dr. Cohen, who has been two decades in the practice, has performed 10,000 circumcisions. He has found the prepuce wanting in 500 cases; partially developed in 300 cases; slightly developed in 2,000 cases. Dr. Gordon has performed 4,400 circumcisions in twenty-five years. He has found the prepuce absent in 15 cases; partly wanting in 200, and slightly developed in 2,200 cases. These, it should be remembered, are only cases where preputial change forced itself on the observer, who was not pursuing investigations on this point.

The volume of Hebrew casuistic religious literature collected in the Medrash, evidences as I have elsewhere shown the frequency of congenital preputial defect.

That acquired characters can be transmitted has been definitely shown by the experiments of George Roe Lockwood, of New York, anent hereditary transmission of mutilations. White mice were selected, as they begin to breed when thirty days old, and breed every thirty days. He bred in-and-in for thirty-six generations, destroying the weakly, and thus obtained finer animals than the first pair. He selected a pair, caged them by themselves, and clipped the tails of the young. When they were old enough to breed, he selected a pair and clipped the tails of their progeny. In the seventh generation he obtained some tailless mice, and finally a tailless breed. The experiments have one possible element of error; white mice, like all albinoes, are a degenerate type. At the same time these experiments show that accidental mutilations favoured by circumstances are inherited.

Eimer reports the case of a pair of long-tailed pointers which had once produced a litter of long-tailed pups. In order to obtain short-tailed pups the owner had the tails of both shortened. The bitch from that time produced repeatedly short-tailed pups only. As the most careful attention was paid to the parents, no error can be suspected in this case, which, moreover, excites no surprise among dog-breeders.

Brown-Séquard has shown that a peculiar alteration of the shape of the ear or a partial closing of the eyelids is inherited by the offspring of animals in which these changes were caused by dividing the sympathetic. Exophthalmia (eye protrusion) was inherited by guinea-pigs in whose parents this protrusion of the eyes had occurred after an injury to the spinal cord, and so were bruises and dry gangrene, as well as other trophic disturbances in the ear, due in the parents to an injury to the restiform body of the brain. Loss of certain phalanges or of whole toes of the hind feet which had occurred in the parents in consequence of division of the sciatic nerve was inherited. Diseased conditions of the sciatic nerve occurred in the offspring of guinea-pigs in which this nerve was divided. Forty guinea-pigs in which one or both eyes showed more or less morbid change were descended from three individuals in which one eye had become diseased in consequence of transverse section of the restiform body. Twenty guinea-pigs exhibited muscular atrophy on the upper and lower sides of the thigh, when in the parents such atrophy had been caused by section of the sciatic nerve.

The experiments of Brown-Séquard, Westphal, Dupuy and Obersteiner, which show that artificially induced epilepsy is inherited, still further bear out the conclusions resultant on the inheritance of these mutilations. Indeed, Weismann has been forced to that reductio ad absurdum in science, narrowly limited definitions, in order to maintain his position. "But although I hold it improbable," he remarks, "that individual variability can depend on a direct action of external influences upon the germ cells and their contained germ plasm, because, as follows from sundry facts, the molecular structure of the germ plasm must be very difficult to change, yet it is by no means to be implied that this structure may not possibly be altered by influences of the same kind continuing for a very long time. This much may be maintained: that influences which are mostly of variable nature, tending now in one direction, now in another, can hardly produce a change in the structure of the germ plasm, and this is the reason why the cause of inheritable individual differences must be sought elsewhere than in these varying influences." "No one has doubted," he says, in reply to objections made by Virchow, "that there are a number of congenital deformities, birth-marks, and other individual peculiarities which are inherited. But these are acquired characters in the above sense. True, they must once have appeared for the first time, but we cannot say exactly from what causes; we only know that at least a great proportion of them proceed from the germ itself, and must therefore be due to alterations of the germinal substance. If Virchow could show that any single one of these hereditary deformities had its origin in the action of some external cause upon the already formed body (soma) of the individual and not upon the germ cell, then the inheritance of acquired characters would be proved. But this no one has yet succeeded in proving, often as it has been maintained."

The crucial test which Weismann demands is furnished by Dupuy, who made one thousand experiments on guinea-pigs to the fifth generation, critically rejecting all results which did not correspond to the most rigid tests of direct heredity, excluding all instances of indirect heredity, however demonstrable. He found that certain lesions of the spinal cord, or the brain or the sciatic nerve, give rise in guinea-pigs to epilepsy.

In from three to six weeks after the operation an alteration in the nutrition takes place in an area of skin which is limited by a line starting from the outer canthus of the eye, and running to the median line on the upper lip, enclosing the nostril, thence backward enclosing the lower jaw, to the anterior portion of the shoulder to the median dorsal line, to the base of the ear and inner canthus of the eye. The alteration in nutrition occurs on the side corresponding to the injury. The pain, heat and cold sense disappear by degrees, while touch appears to be exalted. Very soon, tickling this zone of skin gives rise to twitchings limited to the muscles of the eye and the eyelids on the same side. Later, the muscles of the mouth and of the face are affected, still later the contractions become more general, until the whole side is the seat of convulsions, then the convulsions attack the other side also. When things have come to this point the convulsions precede by a very short time complete loss of consciousness. If the subject of experiment be white, it is found that there is paleness of the face, but in all cases there is little foam at the mouth and dilatation of the pupils. The animal sometimes utters a cry corresponding to the epileptic cry in the man. Not only are the convulsions identical with those in epileptic man, but there is also loss of consciousness, a state of torpor, stupor, and even sometimes insanity. When epilepsy is due to the destruction of the sciatic nerve, the foot of the affected side loses the two outer toes, so that the animal has only one toe, the inner. When young are born to such a parent or parents (for it matters not whether one or both of the parents have been operated upon), they have very often only one toe on the posterior foot. Sometimes, however, they have additional toes, which, in this case, are attached by a pedicle to the limb.

Those peculiarities observed in the parents are in all their details witnessed in the guinea-pigs hereditarily born toeless, who have developed epileptic phenomena. In Dupuy's cases not only is the epileptic tendency (of which Weismann gives a wholly imaginative microbic explanation) inherited, but the very stigmata (loss of toes) which mark development of the parental epilepsy.

E. D. Cope's careful studies of the effects of impacts and strains on the feet of mammals are testimony difficult for Weismann to explain, since they also meet his requirements.

Weismann's admission of the inheritance of a tuberculous habit must logically, from the standpoint of degeneracy, be regarded as destroying his claims.

Kiernan has observed the case of a female cat in which brain mutilation had been induced to secure secondary cerebro-spinal degenerations. The mutilations were made under antiseptic precautions. The descendants of this cat had traces of the mutilation, and its results until the fourth generation, when the breed became extinct. This instance certainly fulfils all Weismann requirements.

In the Lambert family a skin deformity, the last result of degeneracy in previous generations, was transmitted. This peculiarity appeared first, according to Proctor, in the person of Edward Lambert, whose whole body, except his face, the palms of the hands and the soles of the feet, was covered with a horny excrescence. He was the father of six children, all of whom as soon as they had reached the age of six weeks presented the same peculiarity. The only one of them who lived transmitted the peculiarity to all his sons. For five generations all the male members of the family were distinguished by the horny excrescence which had adorned the body of Edward Lambert.

Shwe-Maong, one of the hairless Burmese, when thirty years old had his whole body covered with silky hairs, which attained a length of nearly five inches on the shoulders and spine. He had four daughters, but only one of them resembled him. She had a son who was hairy like his grandfather. The case of this family illustrates rather curiously the relation between the hair and teeth; for Shwe-Maong retained his milk teeth till he was twenty (when he attained puberty); then they were replaced by nine teeth only, five in the upper and four in the lower jaw. Eight of these were incisors, the ninth (in the upper jaw) being a cuspid tooth.

Certain motor expressions of disturbed functions are also inherited. Galton describes the case of a man who, when he lay fast asleep on his back in bed, had the curious trick of raising his right arm slowly in front of his face, up to his forehead, and then dropping it with a jerk, so that the wrist fell heavily on the bridge of his nose. The trick did not occur every night, but occasionally, and was independent of any ascertained cause. Sometimes it was repeated incessantly for an hour or more. The gentleman's nose was prominent and its bridge often became sore from blows which it received. At one time an awkward sore was produced that was long in healing on account of the recurrence, night after night, of the blows which first caused it. His wife had to remove the buttons from the wrist of his nightgown, as it made severe scratches, and some means were attempted of tying his arm. Many years after his death his son married a lady who had never heard of the family incident. She, however, observed precisely the same peculiarity in her husband; but his nose, from not being particularly prominent, has never as yet suffered from the blows. The trick does not occur when he is half asleep, as, for example, when he is dozing in his armchair, but the moment he is fast asleep he is apt to begin. It, as with his father, is intermittent, sometimes ceasing for many nights, and sometimes almost incessant during a part of every night. It is performed, as it was with his father, with his right hand. One of his children, a girl, has inherited the same trick. She performs it likewise with the right hand but in a slightly modified form; for after raising the arm she does not allow the wrist to drop upon the bridge of the nose, but the palm of her half-closed hand falls over and down the nose, striking it rather rapidly, a decided improvement on the father's and grandfather's method. The trick is intermittent in the girl's case also, sometimes not occurring for periods of several months, but sometimes almost incessantly. These "tricks" suggest nocturnal epilepsy, however.

The face of a child is often fully developed, yet, owing to some of the constitutional diseases, arrested development of the face at this point takes place. The second generation inherits this deformity, while the grandparents possess normally developed faces.

The following case came under my own immediate observation. The grandfather was in the habit of sitting in front of the fire with fingers locked together twirling the thumbs in one direction, and then occasionally knocking the thumb nails together. Two of his three sons inherited this habit; the third brother had the habit of biting his nails when in a fit of abstraction. The nephew of the last has a similar habit under the like conditions. The children of this nephew have in two instances shown a tendency to pick at the nails when in an unconscious state, from acute disease. The third child has a periodical tendency to do the same since it was four months old.

V. P. Gibney, of New York, has reported a family consisting of father and mother, five children, and one grandchild. The father and mother are semi-ambidextrous. All of the children and the grandchild are semi-ambidextrous to an annoying degree; all of the movements which they perform with one hand are simultaneously performed by the other hand. The girls are obliged to use only one hand when dressing themselves, or when cutting patterns, and hold the other hand down by their side, because the two hands perform the same movements at the same time and would interfere with each other.

One factor in heredity concerning which there has been much dispute, and whose existence has been denied because of certain theories anent the nerve connection of the mother and foetus, is that of maternal impressions. As Féré has shown, the foetus exhibits very decided reaction to sensory impressions on the mother. He cites cases of several women who, often in the midst of an ordinary dream, producing but very moderate excitation, not generally interrupting sleep, were awakened by foetal movements. The dreams had nothing of the nightmare which would cause sudden contraction under the influence of a terrifying idea. They were merely the ordinary phenomena of sleep. Mental changes of the mother hence excite motor reactions in the foetus, and, as with sensorial excitations, these reactions are stronger in the foetus than in the mother. The mechanism of these motor reactions is, Féré points out, obviously due to unconscious and involuntary movement of the muscle walls of the womb. 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 pregnancy give rise to profound nutritive troubles in the foetus, and especially in its nervous system. These congenitally degenerated beings (ab utero) can hardly be distinguished from those having direct heredity. A considerable number of cases of epilepsy, idiocy, &c., are recognised as having arisen from alcoholism in the mother. Psychic troubles in the mother may react upon the foetus in an analogous way. The prominent facts which show the influence of the psychic state of the mother upon the somatic condition of the foetus explain the action of the imagination of the mother upon the development of the product of conception. The opinion which refers the origin of birth-marks to intense mental impressions on the part of the mother is not without physiological foundation. Concurrently with the motor phenomena, stigmata may become developed by vascular and nutritive troubles produced under the influence of a strong excitation or by the imagination.

Spitzka, who approached maternal impressions from an actively sceptical standpoint, had his scepticism shaken by specimens (preserved in the British Museum) of newly hatched chicks, all of which had a curved beak like a parrot, and the toes set back as in that bird. According to the report of the curator the hens in the farmyard where these monstrosities were hatched had been frightened by a parrot which, having escaped, fluttered among them some time before the eggs were laid and greatly frightened those from whom the malformed chicks were received. It is certain that the chief argument of those who deny that maternal impressions are transmitted is defeated by this case. They have usually asserted that the explanation of the nature and cause of a birth-mark was always an after-thought on the part of the mother. But there was no after-thought in this case. The hens did not publish a theory as to the malformation of their chicks. It was their owner, a gentleman of intelligence and culture, who observed the casual occurrence, and who verified the almost photographic truthfulness of the germ monstrosity by depositing it in a museum as a permanent record at which none may cavil.

Since then, the singular freaks attributable to maternal impressions of women, seen by Spitzka, have become so numerous that he has been compelled to negative the argument that they were merely accidental coincidences. He has never seen an idiotic, malformed child or one afflicted with morbid impulses derived from healthy parents free from hereditary taint in which a maternal impression could not be traced.

In a large number a direct correspondence between the maternal impression and the nature of the deformity or peculiarity could be discovered. He reports the case of a woman, about five months pregnant, who, while standing in her yard, saw her husband stab into the belly of a goat he had slaughtered. The sight of the suddenly protruding visceral mass, which happened to be imperfectly bilobar, shocked her extremely, and, starting back, she, in her great revulsion, feeling a strange sensation at the nape of the neck or back of the head, clutched the former with her right hand. The impression continued to haunt her. When the child was born and she saw its deformity she instantly exclaimed, "Oh, the intestines of that goat!" At the back of its head the child had a large tumour of the consistency of a loose sac of a bluish colour, showing convolutions interpreted by the mother as a reproduction of the intestinal convolutions that had so shocked her. In reality they were the convolutions of a hernia containing the posterior ends of both cerebral hemispheres. The accidental resemblance of the deformity to the mental impressions was striking.

A. Lagorio brought before the Chicago Medical Society several cases in which maternal impressions had produced decidedly abnormal births with deformities resembling those feared by the mother. Kiernan, in discussing these, pointed out that all were instances of checked development. He was of opinion that moral shock, generally directed, played the chief part in maternal impressions through checking development and causing either general or local reversion. Here, as Spitzka shows, the statistical method can be applied. It has been long known that profound grief, mental or physical shock acting on the mother, produce cerebral defect or generally arrested development in the offspring. Of 92 children born in Paris during the great siege, 1870-71, 64 had mental or physical anomalies and the remaining 28 were weakly, 21 were intellectually defective (imbecile or idiotic), and 8 showed moral or emotional insanity. These figures, furnished by Legrand du Saulle, justify the popular designation by the working men of Paris of the defective children born in 1871 as "enfants du siège."

After the great Chicago fire in 1871 birth-marks, deformities, and mental defects were noticed to occur among the offspring whose mothers were pregnant with them pending the exciting time during and after the conflagration.

Spitzka has seen in practice, constitutionally melancholic or mentally defective children in whom no other predisposing cause could be discovered than that the mother was struggling with direct or indirect results of the financial crisis of 1873. In several of these cases the death of the father was a contributory cause of maternal depression. In Berlin the financial crisis of 1875-80 was followed by an increase in the number of idiots born. Lombroso attributes a series of cases of microcephaly to profound mental impressions occurring during pregnancy. To the same class of cases belong the hermaphrodites born by mothers who have been frightened in their first pregnancy and who continue to bear hermaphrodites. The continual and not ill-founded dread that the succeeding children may resemble the first is to be regarded as a contributory cause. Observers who have had a large experience with illegitimate births believe that the mental agony suffered by the unfortunate mother reacts upon the foetus, causing arrest of development, and thus accounting for the frequent occurrence of idiocy in illegitimate children.

The influence of maternal diet on the foetus is excellently illustrated in the results of the "fruit diet" advised by certain vegetarians. Here the children become, as Elise Berwig has recently shown, rickety, irritable, peevish, liable to convulsions, morally peculiar, and otherwise defective in contrast with children born of the same parents without "fruit diet" during pregnancy.

Kiernan, after citing instances reported by Amabile, Carson, F. B. Earle, Erlenmeyer, F. H. Hubbard, C. H. Hughes, Mattison, and others, of congenital opium habit where opium was needed to preserve the infant during the first months of life, states that inheritance of the opium habit seems at first an isolated phenomenon, but zoologists have pointed out that pigeons whose ancestors were fed on poppies became intractable to opium. Murrell found that the same was relatively true in England of persons descended from Bedfordshire ancestors who used infusions of poppies as a prophylactic against malaria. Nervous diseases were, however, relatively prevalent in these districts. Narcotic habits in the ancestors produces descendants in whom the normal checks on excessive nervous action are removed, so that paranoiacs, periodical lunatics, epileptics, hysterics, congenital criminals, congenital paupers, or other degenerates result. This influence is most strongly exerted when the maternal ancestor is the one affected, for to her is committed the development of the ovum prior to conception and of the child subsequently. If either is interfered with by a habit, a being defective in some respects is the result. The direct inheritance of the opium habit has been shown experimentally by Levenstein, who found by experiments on pregnant dogs and rabbits that the use of opium during pregnancy produced either abortion or still-births, or rapidly dying offspring.

In a similar manner Rennert has shown that lead-poisoning occurring in the mother is apt to produce macrocephalism with frequent idiocy in the child.

This brings the observer face to face with the problem of morbid heredity. 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 transmutation 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 class which occurs in frontier communities when the classes begin to be placed in public institutions is an excellent illustration 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 constitutional 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 illustrated 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 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 over forty years ago. This condition occurs, as Féré has shown, 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. Féré 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. Testicle 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 testicle (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 illustrated in the experiments of Dupuy. 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, 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 vagina (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 illustrate 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, "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 constitution. 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 constitution 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, the pioneer American alienist; by Maudsley, by Krafft-Ebing, by Meynert, by Mercier, by Féré, and others. Morel, 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), 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-shell, 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 analogous 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, retardation of conception; third, imperfect conception; fourth, incomplete products (monstrosities); fifth, products whose mental, moral, and physical constitution 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, assume 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 repetition 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 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, C. E. Paddock, 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 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 illustrating excellently the transmutation of morbid heredity is one followed through five generations by Kiernan. 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 sexually inverted masculine daughter, a daughter subject to periodical bleeding at the nose irrespective of menstruation, as well as chorea 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 sexual 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 prostitute, 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 prostitute, dead triplets, a male sexual 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 sexual 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 testicle, 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 testicle, 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.

Strahan gives a genealogy which shows very clearly the close kinship existing between the cancerous diathesis and other forms of constitutional 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 illustrated than in the history of famous families of degenerates like those of the Binswangers, 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) 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 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."