CHAPTER XV
Degeneracy in Reversional Tendencies
The hair 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 defect is 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, sometimes because 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 adopted depends 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.