FIG. 102.
The female type, from the standpoint of bodily and nervous development, most nearly approximates thepromise of the child type, and checks of development will result in masculinism and feminism. In the first the female has proceeded so far in development as to have female organs and their functions while retaining traces of a predominant character of the lower male type. In the second, the male has proceeded along the line of evolution toward the female type, but ere sex has been fixed, further development has been checked and the male type is finally assumed as the predominant one. Both sexes proceed embryologically from an indifferent type nearly resembling the hermaphroditic type found in the lower vertebrates. The arrest of development may therefore take place at any point in the embryonic evolution. The male may preserve only the female breasts[232](Fig.102), while normal in other respects; or, again (Fig.103), present cryptorchidism or sloping shoulders, and be otherwise masculine. On the other hand, his nervous system may have taken such a ply that at the period of puberty the sexual instincts may be female in type. In some instances, this may extend merely to an extreme modesty toward males, to an intense liking for female occupations and disgust for male occupations. In the female precisely analogous conditions may occur. In certain cases the sex side is entirely dormant until awakened at puberty. Education of these cases of arrested development may give the sex direction rather than any in-born tendency. In one case, a male who had undergone arrest of development in his evolution towards the female type was brought up as a girl, had unusually pleasing womanly qualities; as a result was married twice tointensely devoted husbands, and the real sex was never even suspected until post-mortem examination revealed that the supposed woman was a male. In other cases where the nervous system has taken one sexual ply, while the body has taken another, an exceedingly unfortunate class of beings results. This class of beings needs especially careful training during puberty and adolescence. In some instances in addition to the sexual distortion there exist in these beings conditions of mental defect and moral obliquity. In the last case they approximate the criminal type. In the first case residence in an insane hospital protects the community and these beings against themselves. In some instances no mental defect nor, in a strict sense, moral obliquity occurs. Here the patient requires very careful study from every standpoint.[233]There is in the higher and lower races a tendency in different directions as to the predominance of sex. The woman of the lower races more nearly resembles the male of the race. The male of the higher races more nearly resembles in structure the female of his race than does this female the females of the lower race. This is in part due, in the course of evolution, to the intrusion of the male on female occupations, since all occupations, other than war, hunting, and fishing, were created by women.[234]The male, however, in the higher races, while thus taking on the female intellectual and æsthetic qualities, retains the male sexual characteristics, mentally and physically, but in accordance with the law of evolution, these manifest themselves less explosively as in the case of the female. As the victim of masculinism or feminism is a degenerate the explosive manifestations are more marked. Every one of the stigmata of degeneracy already described may coexist with any one of the three conditions named: infantilism, masculinism, and feminism.
FIG. 103.
FIG. 104.
Among the most striking manifestations arisingfrom arrest of development in certain directions with possible hypertrophy in others, are the conditions known as giantism and dwarfism (seeFrontispiece). Both these conditions may be expressions of atavism to no very remote ancestors and present little if any evidences of degeneracy. In other cases degeneracy may be well marked, and the condition be due to imperfect gland action, such as disorder of the pituitary body, which causes very frequently an enlargement of many of the bones ofthe body, and very often a uniform enlargement of all the bones. Indeed, as Marie has said, giantism is acromegaly occurring during the period of adolescence. In many instances the opposite condition, dwarfism, occurs during infancy from causes which check the further growth of the body, although the general functions remain unchanged. Dwarfism is very apt to be attended by preservation of the intellectual faculties without evidence of degeneracy, other than the egotism shown in extreme vanity. Moral defects are, however, more apt to occur in dwarfism than in giantism, in which last condition mental defect is apt to occur, varying from a simple good-humoured stupidity to feeble-mindedness. In proportion as the central nervous system has been affected will the stigmata of degeneracy appear in both conditions. As the line between disease and disordered function is not thinly drawn in these cases, disorders like rickets or local bony tendencies to extensive growth may coexist with both conditions. Infantilism is peculiarly apt to occur with giantism, and while less frequent in dwarfism it also occurs, but is then especially apt to be associated with rickets.
Closely akin to these conditions are leontiasis ossium and acromegaly, both of which are characterised by similar trophoneurotic defects. The first of these conditions may occur precedent to puberty and cease in its completion. Kiernan has observed this in the case of an imbecile on Ward’s Island, who lived until the age of 75, after spending more than sixty years in the charitable institutions of New York. His ancestry was of the criminal and defective classes. Acromegaly is characterised byabnormal growth, chiefly in the bones of the head, face, and extremities. As a rule, the disorder begins at the completion of puberty, although it occasionally occurs at the onset of the climacteric. The illustration given (Fig.104) presents the characteristic features of the disease. In this case there are local evidences of congenital defect. The prevailing trend of opinion is that this condition is due to irregular action of the pituitary body which controls osseous development.
FIG. 105.
As already pointed out in the chapter on Heredity and Atavism, the arrests of development may affect one side of the body, while the other pursues the direct course of development. This may show itself in over-growth, as well as in under-growth, on the affected side. The person may appear, even from the centre of the forehead down, as if the halves of the bodies of two different persons had been joinedin one. Conditions may vary from this extreme type to a state in which a lack of proper nerve and blood supply on the undeveloped side predisposes to attacks of disease, as already pointed out.
Not rarely does it happen that acromegaly attacks the side most deficient in nerve supply. The same is true of allied disorders affecting the growth of the muscles.
The conditions of development may be such that both sides are equally defective in nerve supply, so that when acromegaly occurs it may attack both sides equally. This is particularly apt to be the case with the lower extremities, and enlarged feet (Fig.105) are not an uncommon result.
FIG. 106.
The feet, in addition to the condition already described as being common in both extremities, exhibit special stigmata of their own in consonance with the evolutionary advance which the foot has shown as compared with the hand in man’s evolution. In the lower races the hollow of the foot does not exist, and the condition known as flat-foot occurs (Fig.106). This is usually associated with low instep. It occurs among the stigmata of degeneracy, and is not rarelyassociated with grave moral defects and intellectual distortions. It and other feet degeneracies have been found frequently among paranoiacs, moral imbeciles, and prostitutes. This is particularly true of the prehensile power of the foot.[235]
Degeneracy in Reversional Tendencies
Thehair of the head and body may never develop from the condition of down (lanugo) present in the new-born. The hair over the sexual organs may alone remain in this condition, not showing itself at puberty. In women the hair may be unusually developed on the face and chest. It may also cover the whole body, a condition which is normal in the Ainus of Japan. It may develop, as already shown, very markedly in the lumbar regions.
Speech may be markedly disturbed, reverting to the condition of Haeckel’s Homo-alalus in the shape of deaf-mutism, which is one of the extreme expressions of degeneracy. Not less than 93 per cent. of the cases of congenital deaf-mutism possess deformities of the head, face, jaws, and teeth. The mere fact of the exceedingly primitive structure of the internal auditory mechanism has abnormal or defective hearing power as a consequence. Many cases of congenital deaf-mutism owe their origin to this, inasmuch as the auditory mechanism is not in a condition to appreciate sound, even though the individual may not have been born deaf, and the whole auditory apparatus subsequently degenerates. A mental defectis sometimes superadded, thus aggravating the case. Upon general principles, since deformities of the head, face, jaws, nose, antra, vaults, &c., are common in neurotics and degenerates, stigmata of the ear-bones must occasionally take place. From the complicated structure of the ear, lesions must often result from such deformities. The deaf-mutism here considered is the result of congenital conditions not produced by disease. Dumbness may result from congenital defects of the tongue or deformities of the larynx of an atavistic or a degenerate type, but degeneracy rarely extends so deeply into the organism as in the case of deaf-mutism. No greater error is committed than the confusion of deaf mutism secondary to ear disease with the congenital type.
The most prominent reversional tendencies occur in the genitals. One very common condition is retention of the testicles within the abdomen (cryptorchidism), which has been already pointed out, and may represent the last expiring trace of degeneracy. The testicles may, however, be perfectly normal in structure and function. In the female the uterus may present every type of mammalian uterus from the marsupial up. The female may also revert (as more rarely the male) to the condition of the reptiles and oviparous mammals in which the urinary organs and bowels empty into a single opening, the cloaca. This condition has been found in the female offspring of degenerate families, who are otherwise normal and who have produced children, despite the cloaca.
Another reversion is the occurrence of breasts without nipples, resembling those found in the oviparous mammals. The breasts in degenerates, as already shown, are frequently multiple, sometimesbecause the law of individuation is reversed, but more often as a reversion to the many-breasted condition (polymastia) of the precursor of man.[236]The human kidney and liver may revert not merely in function alone to the sauropsida, but also in structure.
The human heart may present in degenerates all types from the pulsating vessel found in the lancelet up to that of the mammal. The imperfect types of these sometimes perform their functions properly, except under strain. In other cases mixture of arterial and venous blood results, producing the so-called “blue babies.”
Under the teachings of the extreme disciples of Morel, it has been assumed that the family of the degenerate tends to irrevocable extinction. On the principle of individuation already outlined from Spencer, degeneracy, through its tendency to generalise rather than specialise function, causes too rapid development of cells which tend to extinguish each other, thus preventing proper ovulation; and, in the next place, the same condition prevents proper development of the ovum if formed and fecundated; and, finally, causes too numerous simultaneous developments of ova, which would tend to destroy each other. The same cause produces also premature extrusion of ova. At the same time, however, under given conditions, this principle also tends to produce reversions in type in the shape of too frequently repeated and abnormally multiple births. It has been noted that even the ancestors of those predisposed to phthisis have numerous families and many children at a birth albeit most of these die ere reaching the sixth year.Marandon de Monteyel[237]finds that multiple and frequently repeated pregnancies often occur among the families of hereditary lunatics. This has been corroborated by Kiernan[238]and Harriet C. B. Alexander,[239]of Chicago, in connection with the hereditary lunatics in Cook County. They found that 90 families of the hereditary insane averaged 11 children each. Six families had 5 children, 4 had 7 children, 8 had 8, 10 had 9, 14 had 10, 8 had 11, 4 had 12, 4 had 13, 4 had 14, 3 had 16, 3 had 17, 4 had 18, 3 had 19, 5 had 20, and 1 had 21 children, each. Twins, triplets, and quadruplets were six times as frequent as among normal families. Manning has found similar conditions among the hereditary insane in Australia. Valenta, of Vienna,[240]has noted this also among epileptics. He reports the case of an epileptic mother who had 36 children, including six twins, four times quadruplets, twice triplets. Her daughter, also an epileptic, bore 32 children before she was 40, including quadruplets twice, triplets four times, and twins once. Similar, though less striking, statistics occur with other classes of degenerates with proportionate frequency when the sterilising effect of certain diseases to which they are specially liable is taken into account. The general acceptance of the opinion as to large families being a test of advance in evolution seems strange when the extent and force of the action of the principle of individuation is taken into account, and when it is remembered how prolific are the lower vertebrates as compared with the higher.
The origin of tumours on the principle now adopteddepends essentially on that reverse of the principle of individuation, illustrated in plural births.
One most striking expression of nutritive degeneracy is hæmophilia or the diathesis of the “bleeders.” This, as Potain has pointed out, is not met with except in families which are subject to nutritive or graver degeneracies. Dent has shown that definite mental peculiarities, especially an inability (stronger than unwillingness) to tell the truth, are especially common in bleeders.[241]Hæmophilia was frequently encountered in the Valois[242]family, and has been met with in the descendants of Ernest the Pious of Hanover. The condition, as Osler,[243]of Baltimore, points out, is characterised by a tendency to uncontrollable bleeding, either spontaneous or from slight wounds. The hereditary transmission in this disorder is decided. In the Appleton-Swain family, of Reading, Mass., there have been cases for nearly two centuries. Instances have already occurred in the seventh generation. The usual mode of transmission is through the mother, who is not herself a bleeder, but the daughter of one. Atavism through the female is the rule. The daughters of a bleeder, though healthy and free from any tendency, are almost certain to transmit the disposition to the male offspring. The affection is much more common in males than in females, the proportion being estimated at 11 to 1, or even 13 to 1. The tendency usually appears within the first two years of life. It is rare for manifestations to be delayed until the tenth or twelfth year. Families in all conditions of life are affected.Bleeders, like other degenerates, may have large families; the members usually have fine soft skin. In all probability, as the researches of Cohn show, this condition is due to incomplete inhibition, resultant in excessive activity of the blood-making organs. Such inhibition is, of course, cerebral, and hence, as a later acquirement, readily affected by degeneracy which may find its chief expression in this defect.
Among the conditions that have been recognised as an expression of degeneracy is gout, which, as Fothergill long ago pointed out, is a reversion to the condition found in the sauropsidian liver and kidneys. Cullen had previously expressed the opinion that gout is a neurosis. Later researches tend to show that this neurosis is one controlling nutritive tissue change. The condition may occur early in childhood as well as at the periods of stress. The same is true of conditions like arthritis deformans, all of which may be the sole expression of degeneracy in an individual who exhibits many marked stigmata. Another expression of nutritive degeneracy is the senile atrophy of the skin described by Souques.[244]In a case of this kind under my care the patient, a twenty-six-year-old man, was born with club-foot. He has some musical talent. He is a marked degenerate. The skin is thick, coarse, and dry, giving him a very old appearance on account of its shrivelled condition. The ears are undeveloped, eyes small and sunken; excessive development of the cheek-bones; hair coarse and stiff; face arrested in development, possessing a partial V-shaped arch. The width outside first molar is 2; outside second bicuspid, 1·75; width of vault, 1·50; height of vault,·58. One of the prominent features of degeneracy noticed in this case was the lack of hair upon the face.
Disorder of the thyroid produces both dwarfing cretinism, and a myxœdematous condition of the subcutaneous tissues, increasing the quantity of the jelly-like material in these, and therefore approximating some conditions found in the invertebrates. Ichthyosis (the skin disorder producing the “fish men” of shows) is frequently an expression of degeneracy, often associated with deficient limbs and monsters in the same family.
FIG. 107.
A condition due to heredity (involving an arterial change called arterio-capillary fibrosis) underlies many disorders like cirrhosis of the liver, kidneys, and otherorgans. It is usually an expression of premature senescence. Certain families for this reason exhibit a tendency to an early appearance of old age (Fig.107), a tendency which, as Osler remarks, cannot be explained in any other way than that in the make-up of the machine bad material was used for tubing.
Obesity or lipomatosis is a nutritive expression of degeneracy especially noticeable in the second dentition, at puberty, and sometimes at the climacteric. As Féré has shown, lipomatosis (first noticed by Cruveilhier) is an expression of stress at the period of evolution. Youthful obesity occurs in descendants of degenerates. In my experience it is attended by great liability to disease and systemic weakness when under morbid influence. These lipomatosic children are liable to rheumatism (more properly gout) and great hemorrhage from slight causes. Youthful obesity is sometimes, as Féré remarks, associated with precocious maturity and resultant early senescence, but more often with extended infantilism, as in the case of Dickens’s “fat boy.”
In connection with this question of obesity I examined 267 corpulent school children and adults. Nearly all had marked stigmata of degeneracy; 92 per cent. had deformed ears to a marked degree; 66 per cent. had arrested development as compared with their age, while 12 per cent. presented excessive development; 34 were too young to show the final form and size of the jaw. Of the 34, in about 33⅓ per cent., the molars, incisors, cuspids and bicuspids were present; 96 per cent. of these had small teeth. Of the remaining 233, 87 per cent. had arrested development of the upper jaw, 22 per cent. of the lower jaw, 64 per cent. had V or saddle-shaped arches or theirmodifications and protruding teeth; 17 per cent. had hypertrophy of the alveolar process; 83 per cent. had small teeth; 27 per cent. had extra tubercles upon the molars; 82 per cent. had stenosis of the nasal cavity more or less marked; 36 per cent. had deflection of the nasal septum to the left, and 29 per cent. to the right; 21 per cent. wore glasses for eye defects. In 58 per cent. there was enlargement of the thyroid gland, and in 7 per cent. arrest of development of the same.
FIG. 108.
FIG. 109.
FIG. 110.
Among the structures of reversionary type that have attracted most attention of late years is the appendix vermiformis. This, as elsewhere shown, is a rudimentary offshoot which is extremely variable. Man retains this structure as a relic of having been at one time a vegetable feeder. In the koala (Australian native bear), a vegetable-feeding marsupial, it is more than thrice the size of the body. In the carnivora it has entirely vanished. In man, where it is sometimes absent and sometimes is as largely developed as in the orang, it is commonly from four to five inches in length and about a third of an inch in diameter. The appendix is poorly supplied with blood, which predisposes it to attacksby microbes because of the absence of leucocytes to fight these, and also because being, so to speak, a blind ally of the intestine, microbes find in it a suitable culture medium for them. The secretions of the appendix are very apt to decompose: hence a culture medium. The extreme variability of this disappearing organ may be judged from the Figs.108,109,110. As it is best developed in degenerates, it constitutes in them one source of predisposition to death from blood poisoning or from sudden shock. The location of this organ also tends to facilitate disease. In degenerates it may be situatedat any point upon the end of the big bowel, varying from two to three inches. This little bowel is worse than useless in man, being a source of serious danger. It is an instance of checked development of the same kind which causes the human liver to take on sauropsidian peculiarities. Man in this particular as well as the orang is lower than the carnivora, who have lost this worse than useless organ. Its tendency to disappearance in man indicates once more the truth that degeneracy of an organ is often, through the law of economy of growth, for the benefit of the organism as a whole.
I may conclude this outline of human reversionary tendencies by mentioning that merycism, or rumination, has been very frequently found among imbeciles, paranoiacs, hysterics, and epileptics.
Degeneracy of the Brain
Oneillustration, and a very striking one, of the influence of degeneracy on the brain is the durencephalous child which so often appears in degenerate families. Here the cerebral hemispheres and everything but the medulla and pons may be absent, while the rest of the body is in a comparatively normal state of development. Starting with such an extreme expression of degeneracy in the brain, a wide but closely linked range of deficiencies may be found in the brain of degenerates, involving even in some almost normal individuals more than simple deficiency. What was pointed out by Spitzka,[245]of New York, twenty years ago concerning the brain of hereditary lunatics, is equally true of the brains of the other degenerate branches of the same tree. The conventional notion associating idiocy and imbecility with quantitative deficiency of the forebrain only is, as Spitzka remarked, a very imperfect one. The researches of numerous observers have shown that qualitative defects (using the term qualitative in its wider sense to cover both morphologic and histologicaberrations) are as common, and are more characteristic features of the degenerate brain. These defects may be enumerated under the following heads: 1. Atypical asymmetry of the cerebral hemispheres as regards bulk. 2. Atypical asymmetry in the gyral development. 3. Persistence of embryonic features in the gyral arrangement. 4. Defective development of the great interhemispherical commisure. 5. Irregular and defective development of the great ganglia and of the conducting tracts. 6. Anomalies in the development of the minute elements or neurons (as the cells and associating of fibres are now generally called) of the brain. 7. Abnormal arrangements of the cerebral vascular channels. All of these conditions, separately or in the combination of several of the features above mentioned, are occasionally found in the brain of paranoiacs, moral imbeciles, criminals, deaf-mutes and other degenerates. Of the first type the brain (Fig.111), from the practice of Kiernan, is an excellent illustration. This brain came from a paranoiac criminalwho died in the Chicago (Cook County) Insane Hospital. A very similar brain was observed by Kiernan in one of the paranoiacs dying in the New York City Insane Hospital. Similar brains have been observed in deaf-mutes[246]whose mental status passed muster because of the allowance made for mental deficiency due to deaf-muteness. A brain showing as great asymmetry was found in the case of a French physician of standing who was a member of a mutual autopsy society. He proved, however, to have had degenerates in his ancestry and had exhibited peculiarities which showed that much of the degeneracy due to this ancestry had been corrected by proper training. The defects enumerated under Spitzka’s second head are also observable in the illustration given. The gyres are not only asymmetrical as to their number in the two hemispheres, but also as to their size. The contrast between thisbrain and the ideally normal one of themathematicianGauss[247](Fig.112) could not well be greater. Both of these as regards complexity of gyres contrast very decidedly with both the fœtal brain given by Bastian (Fig.113) and the idiot brain (Fig.114) of a patient of Kiernan. The persistency of embryonic features in the gyral arrangement is excellently illustrated in Fig.115, which represents the brain of an imbecile examined by Spitzka. Here the convolutions in general were few, large, and well marked.[248]The occipital and parietal lobes preponderated in mass as compared with the temporal and frontal. The latter were greatly hollowed out onthe orbital face, and the gyri here found were few, simple, and atypical. On the whole the convolutions of the right hemisphere were better marked and the secondary folds more numerous than those of the left hemisphere, and the type of the convolutions presented differences on the two sides. The most pronounced differences were exhibited in the island of Reil and in the occipital lobe. The island of Reil on the left side had fewer and flatter gyri than that of the right side, and resembled in its general aspect the first impression of the brain of an orang-outang. The right island had six folds better marked than those of the left side, but their type was more decidedly radiatory, which was in relation with the unusual shortening of the insular field. The external perpendicular occipital sulcus which Bischoff never found in the adult human brain (but which has been found persistent in a case of imbecility with moral perversion by Sander and in a sane neurotic individual by Meynert) was finely marked upon theright side of the brain under consideration. The fissure was very deep, its posterior wall was slightly bevelled, and covered several secondary gyri of its anterior walls. It differed in position from the similar fissures described by Meynert and Sander in that it did not, as in these cases, unite with the internal perpendicular occipital sulcus and thus simulate the arrangement found in the anthropoid apes. It was merely the unobliterated external occipital fissure of the embryo, and, as in the latter, its medial end if prolonged would have fallen behind the internal perpendicular occipital sulcus. The anomaly consisted therefore in the preservation of an embryonic feature. The arrest of development involved the generally better developed hemisphere. On the left side gyri and sulci were few and simple but typical, the external perpendicular occipital sulcus being interrupted by a broad crossing gyrus. On transverse vertical sections through the hemispheres the average vertical thickness is found to be the same on both sides and normal. The great ganglia were of relatively large dimension, and the white mass of the hemisphere, aside from the internal capsule and the other detachments mediating the connection of the cortex with lower centres, relatively reduced. The caudate nucleus appeared to be of bolder contour on the right side. The right lenticular nucleus presented a larger section area by about 25 per cent. than its fellow of the opposite side. It was much shorter, however, like the insular territory of the same side, and in corresponding sections the posterior end of the left lenticular nucleus was struck while the right was absent. The right nucleus was rounder, the left more triangular incontour in corresponding altitudes. The olivary bodies were asymmetrical, the right one being flatter and smoother than the left. On transverse sections no difference between the olivary nuclei beyond that which occurs in healthy persons could be found; the asymmetry was ascertainably one of prominence only. There was one morphologic appearance noticeable in the fourth layer of the paracentral cortex. This consisted of the presence of round bodies comparable to the nuclei of nerve cells within a thin or no mantle of protoplasm, and presenting every gradation from the free nuclei of the neurolgia, so called, to nerve cells with imperfect processes. These bodies in the human cortex represent imperfectly developed nerve cells and are normally found in the cortex of lower animals. The barren layer or ependyma of the cortex was in places twice as thick in this brain as in the brain of normal beings. This ependyma is the histologic factor of the enormous weight of macrocephalic brains. In a macrocephalic case coming under the observation of Kiernan, of Chicago, in which the brain weighed 68 ounces, the ependyma was five times the normal thickness. The conditions to which Spitzka refers are more or less constantly found in degeneracy. The readiness with which any form of the degenerate series may undergo a metamorphosis into another in the course of hereditary transmission is not, Spitzka remarks, interpretable in any other light than that of the transmission of structure defects either intensified or mitigated in the course of such transmission.
FIG. 111.
FIG. 112.
FIG. 113.
FIG. 114.
FIG. 115.
Transmission of many of these cerebral defects occurs at the moment of conception. The embryonicmechanism of these defects, and the influence which fœtal and maternal impressions and injuries exert on the development of the nerve centres, furnish valuable argument by analogy in support of conclusions regarding the degeneracy group. Embryologists imitate known natural teratological states 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. It is particularly the partial varnishing or irregular heating of the egg-shell that results in the production of anomalies comparable to microcephaly and cerebral asymmetry. The constancy of the injurious effect of so apparently slight an impression as the partial varnishing of a structure not directly connected with the embryo at all, suggests a most plausible explanation of maternal and other impressions acting on the germ. The delicate problems in this connection may be inferred from the observations of Dareste that eggs transported in railroad cars, and thus subject to the vibration and repeated shocks of a railroad journey, are checked in development for several days. A less coarse molecular transmission taking place during the maturation of the ovum or its fertilisation, or, finally, during the embryonic stages of the more complex and hence more readily disturbed and distorted human germ, would account for the disastrous effects of insanity, emotional explosions, and mental or physical shocks of either parent on the offspring.
For the majority of cerebral deformities the causesof the deformity must exist 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 in the fact that the somatic malformation in degeneracy often involves other parts of the body than the nervous axis: defective development of the uro-genital system, deformities in the face, skull, irregularities of the teeth, misshapen ears and limbs.
Those who seek for the source of the arrested or perverted brain development in the reaction of an abnormally growing and ossifying skull on the skull contents are in error. The premature ossification theory does not hold good even for the microcephali; it is to be doubted if it ever had any justification in view of the often open character of the sutures. Taking the well-studied cases of asymmetry, the variability of a single factor shows that caution is needed in referring cerebral anomalies to any single influence. In Muhr’s case (cited by Spitzka) the atrophic cerebellar hemisphere was on the same side with the atrophic cerebral hemisphere. The internal carotid artery of that side was of lesser calibre and the entire skull half shortened. Here the lagging behind in growth of one half of the skull appears on first sight to explain the retarded development of the corresponding halves of the cerebrum and cerebellum. In view of the atypy of the gyri, however, an atypy not to be explained purely on mechanical grounds, it is more reasonable to believe that the imperfect development of certain vascular channels was eitherconcomitant or secondary to a primitive anomaly of the cerebral hemisphere. The retarded skull growth would have to be looked upon as a tertiary occurrence and the cerebellar defect as a final ensuing result. Ordinarily with defective development of one cerebral hemisphere the cerebellar defect is on the opposite side, herein following the course of the anatomical connections of that development and of the secondary degenerations. The deviation from this rule in Muhr’s case was due to the entering of the abnormal skull-shape, itself secondary to other defects, as an element influencing brain growth at a special period of development. An abnormal shape of the skull, generally associated with a cerebral defect, and hence valuable as a physical sign presumably indicating mental anomalies, may exert an important modifying influence at a late period on the contained brain, but the grosser defects in the cerebral architecture must antedate the period of skull growth and be deeply planted as an original intrinsic fault in the brain blastema itself. The researches of His have shown how important for the definitive shape of the body and its organs are the position of individual cells, the portion of the germ area, the convexity and length of germ curves and the relative rate of growth of different germ areas. And as the experiments of other embryologists have established the possibility of producing monstrosities analogous to cerebral defects by altering the conditions ever so slightly, the general conclusion follows that the fundamental error of development at the foundation of malformations associated with degeneracy is to be located at a very early period of embryonic, or possibly of ovuline life. Certain of these anomalies are due to a disturbanceof the balance between the growth of the epiblast and mesoblast derivatives of the brain, others to a disharmony in the development of related associated brain segments; in the severer cases both elements are combined.
It is not difficult to perceive the relation existing between a defective brain weight, paucity of the gyri, deficiency of properly developed cortical cells and such an elementary form of mental aberration as simple imbecility. The subject of the relation between structure and function gains in interest when we leave this domain of simple mental weakness to analyse the relation between structural defects and the positive symptoms of insanity and degeneracy—that is, moral perversion, mental obliquity, delusions, and morbid impulses. Such symptoms are not limited to the higher forms of the degenerate series; they occur, though less constantly and less markedly, in the lower forms.
C. K. Mills,[249]of Philadelphia, on examination of imbecile, paranoiac, and criminal brains, found atypical asymmetry as to gyral and fissure development present. The features of this atypical asymmetry were the existence of a Sylvian fissure shorter on one side than the other, both absolutely and comparatively, and also a more vertical direction of the fissure on one side than on the other, greater exposure of the insula on one side with marked differences in the development of its fissures and gyri, confluence of the central fissure with the Sylvian on one side only, and great tortuosity or bridging of the former fissure in one hemisphere, unusual narrowness, straightness of complication of the precentral or postcentral gyruson one side; marked difference in the simplicity of complexity of the frontal lobes, great simplicity of the orbital surface on one side, differences in the parietal fissure as to length and interruption, a smaller parietal or marginal or angular gyrus on one side, very great difference in the degrees of confluence and interruption of the fissures in general, exceeding great length vertically of the supertemporal or parallel fissure on one side, unusual differences in the size of the precuneus and cuneus.
A. W. Wilmarth,[250]of Philadelphia, Pa., after a careful study of idiots and imbeciles ranging in intellectual power from the idiot, properly so-called, to the juvenile criminal, paranoiac, and “ne’er-do-well,” finds that the brains of these vary greatly along the line pointed out by Spitzka and Mills. One type of brain in this class of children is very simple in its outward configuration. The convolutions are usually coarse, but little convoluted and comparatively free from secondary folds. The fissures tend to assume a confluent type. Another variety, found chiefly among the lowest grades, might well be termed “atypic.” A brain without a corpus callosum is a marked example. In the frontal lobe of the right hemisphere the first frontal convolution is quite regular. Below this from the centre of the lobe seven fissures passed in different directions, cutting the tube into a number of radiating convolutions, entirely different from its usual appearance. The short fissure of Sylvius (about three inches in length) passed upward, turned sharply, and passed almost directly behind. Two parallel gyri curved around its posterior extremity. The arrangementof the convolutions of the temporal and parietal lobes were so exceedingly irregular and complex that it was impossible to classify them. In the occipital lobe, on the contrary, the gyri were complete in number and of regular arrangements. In the left hemisphere the arrangement of the frontal convolutions was more regular, but the temporal and parietal lobes presented the same complicated area of surface folding, bearing but little resemblance to the normal brain. The tendency of the convolutions to arrange themselves in parallel curves around the posterior extremity of the fissure of Sylvius was well shown in the brain of a boy of exceedingly low intellect. The frontal lobes in this brain are proportionately large; the convolutions straight, especially the third frontal, the fissures shallow. In the left temporal lobe they are nearly obliterated from pressure of fluid in the ventricles. The ascending frontal convolution on each side appears to be wanting. On the left side a large bridging convolution crosses the middle of the fissure of Rolando. Confluence of fissure is a decided feature of idiot brains. Even where confluence is not complete, the tendency of the principal fissure to cut through separating convolutions is very evident. Were the cases where confluence is nearly complete included, the number would be considerably augmented. The fissure of Sylvius passed into the fissure of Rolando in one case on both sides, in another on one side only. In two other cases they were connected by deep secondary fissures. The interparietalis has its origin in the fissure of Sylvius in four cases on both sides, in five cases on one side only. The calcarine fissure passedcompletely across the gyrus frontitatus on both sides in two cases, on one side in four cases. In one case the first occipital convolution sank nearly beneath the surface, the next occipital gyrus projecting over it, forming a parietal operculum. There also seems to be a strong tendency to form annectant gyri in the upper part of the parieto-occipital fissure. In no less than six hemispheres of 15 brains were these supplementary gyri found more or less complete. In one case on both sides, in five cases on one side, the parieto-occipital fissure cut through the first occipital convolution into the interparietal fissure. A tendency of the transverse occipital fissure to approach the parieto-occipital fissure is very apparent, though in no case do they coincide. The folds of the cerebral cortex, from a lack of the stimulus of healthy growth, sometimes revert to forms resembling those found in other groups of the animal kingdom.
The fundamental factors of thought and action, as Spitzka terms them, are two: perceptions and motor innervation. These are, in other words, the units of thought and action. They can be properly referred to nerve cell groups as their anatomical seat, and, as far as intellect is in question, to the cell group represented in the more or less diffused and dovetailing areas of specialised function in the cortex cerebri (Fig.116). But the largest hemisphere known, with the most crowded and most highly developed nerve cells, and the most extensive connections with the periphery, and the most perfect projection of that periphery in its intricately convoluted mass would, functionally speaking, represent nothing but a mass of pigeon-holed impressions stored away without method and without purpose, useless to the organismwere it not for those arched fibres uniting the different cortical centres with each other.