CHAPTER VII. Contagious and Infectious Disease

CONTAGIOUS AND INFECTIOUS DISEASE

Among the gains of human advance in evolution stand out prominently complete immunity from certain diseases due to germs, and partial immunity from others, which last immunity results in chronic types, rather than in acute, because of increased vital resistance in man. Tuberculosis and dourine, acute diseases in the cow and horse, have become chronic diseases, tuberculosis (or consumption) and syphilis, in man. Such chronicity is evidence of advance, yet it constitutes an element of degeneracy, since the victim of the chronic disease is able to leave more offspring than would be possible were the disorder acute. In other respects acute and chronic contagions and infections exert the same influence in regard to degeneracy. The germ of the disease may be inherited, or general nutrition of the foetus may be so checked in development that the child inherits a predisposition to disease.

Through this check to foetal development the phagocytes, or white blood cells, become so weakened that they are unable to devour foetal structures as useless to man as the tadpole's tail (which it devours) is useless to the developed frog. This power being weakened, the organs which form antitoxins (or protective tonics against disease), from lack of development fail to perform their function. For this reason in the degenerate many infections and contagions assume their old destructive type.

The influence of these disorders in the parent may result in the bony mal-development shown to occur in animals by Charrin and Gley, and in man by Coolidge. The facial bones, jaw, and teeth are peculiarly liable to be thus affected. Though the effect of the disease on the parent be but temporary, the child's development may be checked as to higher tendencies. Thus mothers have borne moral imbeciles, epileptics or lunatics, after a pregnancy during which they were attacked by contagious disease, albeit the children of subsequent and previous pregnancies were normal.

The children of pregnancies previous to the one complicated by the contagious disease may be healthy, while those of subsequent pregnancies are defective. Any contagious or infectious disease may not only interfere temporarily with the bodily strength, but may produce complete change in the parent's system extending even to the highest acquirement of man. In some occur changes thus graphically described by Bulwer: "There have been men who, after an illness in which life itself seemed suspended, have arisen as out of a sleep with characters wholly changed. Before gentle, good, and truthful, they now become bitter, malignant, and false. To those whom they before loved they evince repugnance and loathing. Sometimes this change is so marked and irrational that their kindred ascribe it to madness. Not the madness which affects them in the ordinary business of life, but that which turns into harshness and discord the moral harmony which results from natures whole and complete."

The nerve centres controlling nutrition, growth, repair, secretion, and excretion are often as deeply affected as those checks constituting morality. At the periods of physiologic stress these effects are especially noticeable. Moral insanity, intellectual insanity, unequal mental balance, hysteria, precocious sexuality, unconscious mendacity, mental parasitism (the germ of pauperism), epilepsy, neuroses, and all types of nutritive and constitutional defects result. The nutritional defects may appear chiefly in the walls of the blood vessels and lymphatics. While these are most common in the chronic infections and contagions, they often occur in acute typhoid fever, scarlatina, diphtheria, whooping-cough, &c. Proper blood supply and utilisation of waste is thus prevented. Organs cannot perform their function, and are predisposed to disease from disuse and from weakness of the disease-fighting phagocytes and antitoxins. From this results irregularity of organ function, which is hereditarily transmissible. The weakened vessel walls yield to strain, and thus produce local stomach, bowel, liver, gland, and kidney disorders. This organ weakness may alone be transmitted to the offspring. The functions of the great glands (thyroid, thymus, suprarenals, pituitary body, bone-marrow, testicles and ovaries) which secrete principles necessary to the equal balance of nutrition are perverted. The liver, in the acute but more particularly the chronic contagions, paralysed in nerve tone, fails in its function of poison-destroyer, as for the same reason the kidneys fail in their power of ejecting hurtful waste. Through this interaction of perverted nutrition, imperfect poison-destruction, and deficient waste ejection result and continue the states of nervous exhaustion after the contagions and infections. Thus nerve exhaustion with its suspicion, its capricious hopefulness and gaiety, is practically continuous in tuberculosis, syphilis, and leprosy.

The acute and chronic contagions and infections so lower cell vitality through the perverted functions described that inert connective tissue replaces healthy working cells. This is especially the case with syphilis, which, when driven from the system, leaves behind it a tendency to disease based on this connective tissue increase. This tendency, latent in the ancestor, may be so intensified in the descendant as to produce the hereditary ataxias (loss of movement power), and like neuroses. At the periods of stress such tendencies are peculiarly potent, and not only check, but reverse development. The chronic contagions and infections are most fertile sources of human degeneracy since their weakened products are enabled to survive under modern beneficence. Of these chronic contagions two (tuberculosis and syphilis) alone deserve attention, since the third (leprosy) exerts but little influence. Despite its existence for more than a century (New Brunswick and Nova Scotia on the north and Louisiana on the south) on the borders of the United States, despite its subsequent importation from Norway, Sweden, China, and Hawaii, its spread has been infinitesimal, and its influence on race deterioration is still less demonstrable.

Tuberculosis ("the white death") is from every standpoint a social danger more serious than syphilis. The father, as in syphilis, can infect the mother, but sterility is much less likely. As has already been shown in the chapter on heredity, plural and quickly repeated birth are common in tuberculous families. The tuberculous diathesis (or "habit," as Weismann calls it) was very early observed in the United States. Nearly seventy years ago W. P. Dewees, of Philadelphia, pointed out its frequency and its early observation by the Greek and Roman physicians. He cites a case illustrative of the extent and uniformity of diathesis in a very numerous family. This predisposition arose on the side of the mother, though she lived herself to the age of forty-three, a period much exceeding that of any of her children, with the exception of a son, who died in his forty-fifth year. This lady bore twenty-three children without being able to suckle any but the two first. The males much exceed the females in number, yet there did not appear to be any exception to their favour in the transmission of the phthisical taint, except that they attained in general a greater age before they died. Some died about puberty, others at manhood or womanhood; but all, with the exception just stated, under thirty. The disease was never very rapid; they generally complained from one to two years before they died. The men had a healthy, even in some instances an athletic, appearance until the disease became open and decided. In their growth and stature they altogether resembled the father, who was not only a remarkably stout man, but lived beyond the eightieth year. The females, who passed puberty (two in number) were rather stout women, while the mother was both delicate and small. This family lived in the country, was very wealthy, and always accustomed to the various means generally found successful either in destroying the predisposition or lessening its influence, yet in no one instance in this family were they successful, though the open form of the disease was retarded perhaps in all. The females died the earliest.

The blood vessel system is affected as regards development in such families. The heart is often diminutive; the right ventricle is exaggerated. Two great types of degenerate constitutions are produced in children of the tuberculous. One of these may well come under De Giovanni's category of the torpid. The victim is usually coarse-featured and coarse-skinned, with peculiarly unstable mentality; slowness of comprehension is combined with power of continuity of thought; at times mental apathy alternates with quickness of perception. Decided exaggeration of the lymphatic system (connected with utilising of material elsewhere than at the point where it has been rendered unfit) with deficient function occurs, resulting in fitting a soil for germs. In other respects the torpid resembles the second type, the erethistic (nervously fussy type) of De Giovanni. This is generally characterised by the presence of a clear complexion, a fine skin, and features well cut and often beautiful. The lips are red and the teeth pearly white, though liable to early decay, and the eyes are large and full, the pupil being widely dilated and the white of the eye beautifully clear. The eyelashes are long, curved and silky, and the blue veins show distinctly through the clear thin skin. The bones are light, the hands and feet well formed, the stature often tall, and the whole figure slightly and gracefully built. The erethists generally remain spare, and have a strong dislike to fatty food. They are vivacious and excitable, and the intellectual faculties are often highly developed. At an early age they show marvellous activity. The regularity with which such precocious tubercular children die has given rise to proverbs anent exceptionally clever children that they are "too wise to live long." Wanting in stamina, they are incapable of prolonged exertion either of mind or body, and break down under conditions which would not prove injurious to the healthy. They are continually taking "cold," and are prone throughout life to affections of an inflammatory character. Multiple and frequent pregnancies occur. The children, deficient in vitality, are carried off in numbers during infancy by convulsions, brain fever, water on the brain, exhaustion, diarrhoea, teething, and other ailments, or they succumb at the second detention or at puberty. A small proportion reach maturity. Few live beyond thirty-five or forty years of age. However brilliant intellectually, they are equally emotional, impressionable, and impulsive. There is a marked absence of mental stability. They are suspiciously capricious. The great secreting and eliminating glands undergo with peculiar frequency the perversions already described.

Neuroses and psychoses are peculiarly frequent in childhood and youth. The degenerative power of tuberculosis is not always due to the influence of the germ, or even of the toxin produced by it, but to the state of nerve weakness resultant on the disorder. The victim of tuberculosis (especially if affecting the lung) is a suspicious, yet hopeful, nervous invalid, whose functions are irregularly performed and who is therefore likely to leave scions with greater defect, especially as the maternal factor, either through infection or worry, can hardly escape being weakened. Tuberculosis attacks the bones of the offspring, especially the spine and hip-joint, but the victim of these last frequently regain health after apparent recovery from the local disease through surgical procedures. If the victim of the hip-joint disorder be of the erethist type marriage is not unlikely. Despite the deformity produced by spine disorder, popular superstition as to the "good luck" of a hunchback leads to marriage among the working class. Monetary and social considerations effect the same result among the wealthy classes. Here deformity does not prevent marriage, but predisposes to sterility through birth difficulty.

The influence of syphilis is, in a general sense, the same as that of tuberculosis, except that by reversing the principle of individuation it leads to greater sterility. Furthermore it exhibits greater tendencies to revert towards health, and yields (even in the inherited form) more to medicinal treatment. The inherited form at times presents itself in two types closely simulating those due to tuberculosis. Like the bacillus of tuberculosis, the syphilitic germ attacks every structure and organ of the body. Its reversal of the principle of individuation, causing excessive cell formation, produces more decidedly demonstrable effects. As syphilis is more apt to attack the central nervous system than tuberculosis, it would seem that it is a greater race-deteriorating factor. The excessive tendency to cell formation, however, produces impotence in man, sterility and abortion in woman. There are very good reasons for believing that the race is becoming immune to syphilis, and that this disease will disappear. Its greatest race-deteriorating effect is in preparing the soil for tuberculosis and other infections and contagions.

The influence of contagions and infections on degeneracy is therefore by no means slight. Each disease can produce grave constitutional defects in the ancestor likely to be intensified in the offspring. The greatest social dangers result from tuberculosis; the next from syphilis. Typhoid fever, scarlatina, small-pox, measles, diphtheria, whooping-cough, and all other contagions, however, may produce these constitutional defects, either through the mother during pregnancy or through their secondary effects on the ancestor's constitution. If the subject be attacked before the close of the periods of dental stress an arrest of development of the bones of the face may result with irregularities in the shape and position of the teeth. These, then, are stigmata of degeneracy, especially due, in the individual presenting them, to the contagions and infections rather than to inheritance alone.