Hereditary disease

“ The Furies still ply their work of terror and death; but we have stripped them of the garb which superstition threw around them, and they now appear to our eyes in the more intelligible but not less awful form of hereditary disease. Modern science, which has cast illumination into so many dark corners of Nature, has shed a new and still more lurid light on the words of the Hebrew Scripture: "The sins of the fathers shall be visited upon the children unto the third and fourth generation." Instances of hereditary disease abound on every hand. ”

“ Instead of the old shadow of {179} heredity with its supposedly almost inevitable fatality, so that young people who saw their brothers and sisters or other relatives around them die from the disease felt that they were doomed, we now know that the hereditary factor plays an extremely minor role if indeed it plays any serious rôle at all in the development of the disease. ”

“ In short, the predisposition to disease may be hereditary or congenital. Hereditary transmission is, however, not inevitable, and most frequently it is due to very diverse conditions in the nutrition of the progenitors. Some authors have associated the idea of degeneration with that of heredity, and designate a whole category of disorders under the name of hereditary degenerations; but many persons who exhibit the characteristics of this category have not inherited them. ”

“ Black suggests that some of my arguments might be used to disprove the hereditary tendency of insanity and consumption. Before the doctor's friends permit him to undertake another pathological controversy, I would advise them to enlighten his mind on the difference between functional and organic disorders, and thus enable him to understand the reason why consumption or cancer, but not dyspepsia, can be called an hereditary disease, and why hereditary diseases and not dyspepsia reappear in successive generations at the same period of life when they were first contracted. ”

“ The law of homochronous heredity, or the reappearance of hereditary characteristics at the same periods of life in ascendants and descendants.
Morbid heredity does not inevitably obey the laws of direct heredity. It is a well-known fact that diseases in morbid families are not usually transmitted with a perfect likeness. The homologous or similar heredity, which is observed chiefly as to mental diseases, is rare as to other diseases. Usually the disease is modified in descent. A diabetic patient produces an ataxic son, or a hysterical daughter, or an epileptic child. ”

“ Phthisis and scrofula placed by themselves in this group share in this decrease. In the second group are diseases that are due in great measure to carelessness, want of management, neglect and ignorance, such as convulsions, diseases of dentition, parturition and registered accidents. These, too, as one would expect, diminish yearly in a country where surrounding comforts and a sense of responsibility are on the increase. When we turn to the third group, that of constitutional disease, where the hereditary tendency comes in, we find an increase in almost all the hereditary diseases. ”

“ The third group holds that cousin marriages in themselves, especially if not carried through too many generations, are not harmful, but that if any hereditary tendency to malformation or disease exists in the family of the parents, this tendency, inherited through both parents is strongly intensified in the offspring, and that consequently an increased percentage of the offspring of cousin marriage may be afflicted with hereditary diseases. ”

“ Again, with respect to atavism and to the hereditary transmission of latent qualities, it is questionable whether, in cases in which the subject of investigation is not himself affected with disease, but his near relatives are so affected, we have reason to fear the hereditary transmission of harmful consequences to the offspring. It is especially with regard to the male sex that the question of the hereditary transmission of morbid qualities is so important, for, in marriage, it is the male partner who contributes the greater proportion of the diseases. ”

“ Now, the longer the diseased parents, with medical assistance, can drag on their sickly existence, the more numerous are the descendants who will inherit incurable evils, and the greater will be the number of individuals, again, in the succeeding generation, thanks to that artificial “medical selection,” who will be infected by their parents with lingering, hereditary disease. ”

“ We have seen intire families infected; and almost every child of a leprous father or mother fall insensibly into the leprosy; and yet, in several other families, we have seen some children sound, and others tainted; the father has died of the disease, and the children grew old without any infection: so that, tho' it is certainly hereditary, yet we believe it is of the same nature with those in families troubled with the consumption, gravel, and other hereditary distempers; which are transmitted from father to son, without being so very regular, as to affect every one of the family. ”

“ If the parents possess good vitality and pure, normal blood and tissues, and if they apply in the prenatal and postnatal treatment of the child the necessary insight and foresight, there cannot be disease heredity. In order to create abnormal hereditary tendencies, the parents, or earlier ancestors, must have ignorantly or wantonly violated Nature's Laws, such violation resulting in lowered vitality and in deterioration of blood and tissues. ”

“ A few of the various defects which seem to be inherited as recessives when mated with normality are: susceptibility to cancer; chorea (St. Vitus’ dance) ; true dwarfism (all parts proportionately reduced) ; Alkaptonuria (urine darkens after passage) ; alcoholism and criminality, where based on mental deficiency; hereditary hysteria; multiple sclerosis (diffuse degeneration of nervous tissue) ; Friedreich’s disease (degeneration of upper part of the spinal cord) ; Merriere’s disease (dizziness and roaring in ears) ; [Pg 118] Thomsen’s disease (lack of muscular tone) ; hereditary ataxia ”

“ The most eminent physiologists of the age concur in the opinion that, of all the causes which predispose to nervous and mental disease, the transmission of hereditary tendency from parents to children is the most powerful, producing, as it does, in the children, an unusual liability to those maladies under which their parents have labored.
When both parents are descended from tainted families, their progeny, as a matter of course, will be more deeply affected than where one of them is from a pure stock. ”

“ Inquire and see if like causes acting on like organisms in 3 or 4 successive generations have not produced the disease each time. The children are not born cancerous, and our efforts to prevent the disease may succeed. But children often are born with specific disease, and there is no doubt at all about its being a hereditary disease. ”

“ The question of the inheritance of diseases may be briefly considered here. If a disease is due to some defect in the hereditary constitution, it is inherited; otherwise, according to our definition of heredity, it is not. Of course no disease develops without extrinsic causes but when one individual takes a disease while another under the same conditions does not, the differential cause may be an inherited one, or it may be due to differences in the previous conditions of life. ”

“ This supervision should be carried into adult years, for there are instances on record of inherited diseases coming on at an advanced age, as in that of a grandfather, father, and son, who all became insane and committed suicide near their fiftieth year. Gout, apoplexy, insanity, chronic disease of the heart, epilepsy, consumption, asthma, and other diseases, are all more or less under the control of preventive measures. Some hereditary diseases, such as idiocy and cancer, we are impotent to prevent, in the present state of our knowledge. ”

“ Tuberculosis, rheumatism, gout, various nutritional disturbances all were supposed to pass from father to son and from mother to daughter, or sometimes to cross the sex line. For a time cancer was deemed to be surely hereditary to some degree at least. Now most of us know that probably no disease is directly inherited, that acquired characters are almost surely not transmitted, and that while defects may be the subject of heredity, disease never is. Not only this, biological investigations have served to show that what is the subject of inheritance is just the opposite,--resistance to disease. ”

“ In the many family suits argued by the Attic orators, we do not (I believe) find a case in which a large family of children is concerned. Four appears a larger number than the average. Marriages between relations as close as uncle and niece, and even half-brothers and sisters, were not uncommon; but the researches of modern science have removed the grounds for believing that this practice would tend to diminish the race. It would certainly increase any pre-existing tendency to hereditary disease; yet we do not hear of infantile diseases any more than we hear of delicatep. ”

“ Equally difficult is the question of hereditary diseases; this is now generally assumed to depend on the transmission of a predisposition which is present, though not recognizable, in the earliest cells, being derived from the parental or maternal tissues. But the most elaborately constructed doctrines as to the hereditariness of a given disorder may break down before the discovery of an actual causa viva. ”

“ Inheriting Disease. Consumption—that dread foe of modern life—is the most frequently encountered of all affections as the result of inherited predispositions. Indeed, some of the most eminent physicians have believed it is never produced in any other way. Heart disease, disease of the throat, excessive obesity, affections of the skin, asthma, disorders of the brain and nervous system, gout, rheumatism and cancer, are all hereditary. A tendency to bleed frequently, profusely and uncontrollably, from trifling wounds, is often met with as a family affection. ”

“ We cannot speak of heredity in connection with diseases to which all are susceptible and incapable of developing immunity. The presence or absence of such a disease is determined solely by the presence or absence of infection. Many physical and mental defects result from infection as the primary cause. If the infection is one to which all exposed are susceptible and incapable of developing immunity we cannot speak of the defect as in any way hereditary ”

“ I do not observe so great a difference in the recovery, from either age or cause, as might be expected: there are cured and incurable, promiscuously at all ages; and from all the different causes, whether adventitious or hereditary. Even from hereditary insanity, they seem to recover nearly as well as from the less inherent causes: there are several instances of recovery when hereditary from the parents on both sides. In some, where the disease was entailed, it has made its first appearance in all the intervals from puberty to fifty years of age. ”

“ This disease cannot be propagated by contact or contagion; it exists in individuals in whom there is a peculiarity of constitution which predisposes them to its attacks; and this brings me to the consideration of one of the most important causes of the disease, namely, an hereditary taint. ”

“ And looked at thus, we know of no specific disease which can be called hereditary. The conditions which are hereditary are all anatomical and physiological peculiarities of the organism. A bacillus which is living in the organism cannot be regarded as one of its anatomical or physiological peculiarities; it is a parasite. ”

“ So far we have considered the causes of mental deficiency of hereditary origin. The causes in general may be grouped roughly under direct, which are due to heredity or disease, and indirect, due to sense defects and accidents. About 85 per cent, of the cases may be traced to conditions prior to birth, such as bad heredity, neurotic conditions, alcoholism and tuberculosis. Injuries at birth are at the present time rare and are responsible for not over 1 per cent., according to the best authoritories. ”

“ Where, however, the hereditary tendency is to a disease likely to manifest itself in childhood or youth, a member of such a family who has been fortunate enough to pass through the years of development without exhibiting any pronounced disturbance of the nervous system, may be permitted to marry if certain precautions are observed. ”

“ For example; the same motions which made the Gout in the Parent, may make the same disease in the Child; but every Child has not his Parents diseases, and many Children have such diseases as their Parents never had; neither is any disease tied to a particular Family by Generation, but they proceed from irregular motions, and are generally in all Mankind; and therefore properly there is no such thing as an hereditary propagation of diseases; for one and the same kind of disease may be made in different persons, never a kin to one another, by the like motions ”

“ We have thus an American survey of the subject by a surgeon, with the suggestions of a good zoologist, and on the subject of evolution the special standpoint of the author should always be understood.
Dr. Shute's special knowledge thus enables him to point out the confusion of thought which often fails to discriminate between heredity and pseudo-heredity, even physicians frequently writing of certain diseases as hereditary, whereas congenital bacterial infection, or the transmission of a microbe of the disease through the germ-cells of the parents is the correct explanation. ”

“ This affection is certainly hereditary in some cases, and it may well have been explained as an example of the transmission of acquired changes. It has been argued that acquired short-sightedness can be in a slight degree transmitted, and that each successive generation has developed a further degree of the disease by habitually holding books etc. close to the eyes, so that the inborn predisposition to short-sightedness is continually accumulating. ”