DANBURY, CONN., DECEMBER 15, 1888. ORIGINAL LECTURES. HEREDITY—A PHYSIOLOGICAL BY THOMAS M. DOLAN, M. D., FELLOW OF A Lecture delivered to the Halifax Scientific (Continued from page sixty.) As regards diseases that pass in the hereditary line Richardson says we must admit the following as proved:Scrofula, struma, gout, insanity, cretinism, albinism, syphilis, consump tion. 29 1. The insanity of the mother, as regards transmission, is more serious than that of the father; not only because the mothers disorder is more frequently hereditary, but also because she transmits it to a greater number of children. 2. The transmission of the mother's insanity is more to be feared with respect to the girls than the boys; that of the father, on the contrary, is more dangerous as regards the boys than the girls. 3. The transmission of the mother's insanity is scarcely more to be feared, as regards the boys, than that of the father; it is, on the contrary, twice as dangerous to the daughters. Consanguinity, or the marriage of relations, has a powerful influence on insanity and the allied diseases. This list might be extended, for we are day by day learning new facts and fresh observations are being produced, Dr. Buniss has published some imowing to the impetus given to the study portant facts bearing upon this quesof heredity, by the philosophy of evolution, which I extract from the Medico tion. I shall dwell for a short time on the subject of insanity. Esquirol observes that of all diseases Insanity is the most hereditary. Hereditary predisposition is a term often made use of to comprise many different degrees of consanguinity; it is sometimes used to signify direct ancestors only, and such evidence is by far of the greatest value. It may mean the existence of insanity in the uncles and aunts of any prior genera tion. also M. Baillarger31 has arrived at the following conclusions in reference to the influence of the father and mother in transmitting insanity: 28. Philosophical Transactions, Vol. XVII. and Vol. XLIX. Chururgical Review for 1860, Of 31 children of brother and sister, or parent and child, 29 were defective in one way or another; 19 were idiotic, 1 epileptic, 5 scrofulous, and 11 deformed. Of 53 children born of uncle and niece, aunt and nephew, 40 were defective; 1 deaf and dumb, 3 blind, 3 idiotic, 1 insane, 1 epileptic, 12 scrofulous, and 14 de formed. Of 234 children born of cousins themselves, the offspring of kindred parents, 126 were defective; 10 deaf 29. Diseases of Modern Life, p. 28. dumb, 2 blind, 4 idiotic, 6 insane, 2 epileptic, 10 scrofulous and 2 deformed. In connection with insanity I shall now allude to alcohol, the influence of which upon heredity is very great. We have, according to Carpenter, a far larger experience of the results of habitual alcoholic excess, than we have in regard to any other "nervine stimulant" and all such experience is decidedly in favor of the hereditary transmission of that acquired perversion of the normal nutrition which it has engendered in the individual. That this manifests itself sometimes in congenital idiocy, sometimes in a predisposition to insanity which requires but a very slight exciting cause to develope it, and sometimes in a strong craving for alcoholic drinks, which the unhappy subject of it strives in vain to resist, is the concurrent testimony of all who have directed their intention to the inquiry. Thus Dr. Howe, in his report on the statistics of idiocy in Massachusetts, states that the habits of the parents of 300 idiots having been learned, 145 or nearly onehalf were found to be habitual drunkards. In one instance, in which both parents were drunkards, seven idiotic children were born to them. Dr. Down whose experience of idiocy is greater than that of any other man in this country has assured Dr. Carpenter that he does not consider Dr. Howe's statement at all exaggerated. Dr. W. A. F. Browne, the first Medical Lunacy Commissioner for Scotland, thus wrote when himself in charge of a large asylum. "The drunkard not only injures and enfeebles his own nervous system, but entails mental diseases upon his family. His daughters are nervous and hysterical; his sons are weak, wayward and eccentric, and sink under the pressure of excitement of some unforeseen exigency or the ordinary calls of duty." Dr. Howe remarks that the children of drunkards are deficient in bodily and vital energy, and are predisposed by their very organization to have a craving for alcoholic stimulants. If they pursue the course of their fathers, which they have more temptation to follow and less power to avoid, than the children of the temperate, they add to their hereditary weakness, and increase the tendency to idiocy or insanity in their constitution; and this they leave to their children after them. Elam well says the punishment does not only descend upon the individual concerned. There is no phase of humanity in which hereditary influence is so marked and characteristic as in this. The children do unquestionably suffer for or from the sins of the parent, even unto untold generations. And thus the evil spreads from the individual to the family, from the family to the community, and to, the population at large, which is endangered in its highest interests by the presence and contact of a morbid vanity in its midst. The history of four generations in one family, sketched by M. Morel is full of instruction. It includes father, son, grandson and great-grandson. 1st Generation-The father was an habitual drunkard and was killed in a public house brawl. 2nd Generation-The son inherited his father's habits, which gave rise to attacks of mania, mania, terminating in paralysis and death. 3rd Generation-The grandson was strictly sober, but was full of hypochondrical and imaginary fears of per32. Carpenter, Mental Physiology. secution and had homicidal tendencies. 4th Generation-The fourth in descent had very limited intelligence, and had an attack of madness when sixteen years old, terminating in stupidity nearly amounting to idiocy. With him probably, the race becomes extinct and thus we perceive the persistence of the taint in the fact, that a generation of temperance did not avert the fatal issue. When in a society, a people or a race, we find that the moral and intellectual powers have undergone considerable degradation that maladies, up to a certain time unknown, now have a serious influence on the public health; that the numbers of insane persons and criminals increase in great proportion,we have a right to conclude that a cause which in individuals and families produces certain results, is likely, if in operation, to have done the same thing in larger communities. a We need not wonder at the active crusade now going on against alcohol in the face of these facts, supplemented by so many others derived from knowledge of the injurious effects of our drinking customs; we are all aware, from the statements and published papers of temperance advocates, from personal experience, that alcohol is one of the most dangerous agents we have in our midst, that its fruits are seen in our prisons, workhouses, asylums; in ruin and misery; in broken hearts and ruined homes, that it penetrates every state of society; so I think we must all agree that temperance reformation is worthy of support and we must wish it success. A great practical question arises from the preceding facts. Can the child of a drunken father or mother escape from the results of his progenitors vice? Can he emancipate himself from the tendency to drink? I can answer this in the affirmative! He can. I know of many instances, from my own professional and personal experience, where men knowing that they had an hereditary taint, carefully guarded against the agent which they knew was dangerous to them. Totol abstinence is the only safeguard, but it is a certain one. It involves negation of what many men find pleasurable, but life is made up of sacrifices, and the struggle of will against desire is carried out daily by thousands of self-abnegating individuals, who give up something, may be for themselves or for others. The victory over self is all the more noble because of the internal contest, and of the very sacrifices made to secure it. I have mentioned insanity in connection with the physical though by many it would be classed with the psychical, but at the present day it is regarded as an axiom, that every psychological state corresponds to a determinate physiological state or in other words that disorders of the intellect have corresponding to them evident changes of the tissues of the nerve centres, though in some cases there is no degeneration appreciable to the eye or the microscope. Passing on to other endowments I may mention first, Heredity of the Sensorial qualities-as touch, sight, hearing, smell and taste. As regards the sense of sight I may particularly allude to the incapacity of distinguishing colors, known under the name of Daltonism or color blindness. This is notoriously hereditary. The distinguished English chemist, Dalton, was so affected, as were also two of his brothers. Sedgwick discovered that color blindness occurs oftener in men than in women. In eight families akin to each other, this affection lasted through five generations, and extended to 71 persons.33 This form of visual imperfection is very important. You know that employes on railways, steam boats are very much guided by green and red lights, if they are color blind they are unable to distinguish them. Accidents have happened owing to this defect, and hence all such employes should be examined and their power of vision tested. Heredity of the memory and imagination I may take next though there is not much evidence as to the former. There are two kinds of imagination -the one productive and the other creative, and with the later I shall deal. We find the active imagination of the poet, the artist, the musician, and even. of the man of science. transmitted. men, drawn out their genealogies, traced their relationships, compared the results, struck averages, and the following are the conclusions: He first entered this field with a work on English judges from 1660 to 1865. These judges constitute our highest magistracy and are universally admitted to be exceptional men. Their biography is known, as are also their family connections. Here, then was a fair number of facts, which might be grouped together, in order to examine the results. In the course of 205 years there were 286 judges and among these Galton has found 112 who had one or more illustrious kinsmen. Hence the probablity that a judge has in his family one or more illustrious members exceeds the ratio of 1.3-in itself a striking result. If we now pass from this partial work on the judges to broader researches, we meet with results of very much the same kind. The lives of poets, musicians, painters, sults to details it may be shown how Passing now from these general re show that we have a sufficient mass of data for the assertion that talent or genius of this kind is hereditary. I have alluded to Galton's work on hereditary genius—a work of immense labor and research. Ribot has ably analyzed his work. I place before you the results. Galton placed before himself these questions: Is genius hereditary and to what extent? Given an illustrious and eminent man what are the chances of his having had an illustrious father, grandfather, son grandson, brother? To answer this question, the author has searched the biographies of great 33. Darwin, Variation of Plants and Animals, ii, p. 70. this probablity diminishes as we pass from relations of the first degree (father, son, brother) to relations of the second degree (grandfather, uncle, nephew, grandson) and those of the third degree (great-grandfather, granduncle, cousin, grand-nephew.) Suppose 100 families of judges and let N stand for the most eminent man in each of them, the number of their illustrious kinsmen will on the average be distributed as follows: Father, 26; brother, 35; son, 36; grandfather, 15; uncle, 18; nephew, 19; grandson, 19; great-grandfather, 2; grand-uncle, 4; first cousin, 11; grand-nephew, 17. This statement will be more readily understood from the following table: TABLE I. 2 Great-Grandfathers, 15 Grandfathers, 4 Great Uncles, 26 Fathers, 18 Uncles, 100 N, 35 Brothers, 11 Cousins German, 36 Sons, 19 Nephews, 19 Grandsons, 17 Grandnephews, 6 Great-Grandsons. Galton distributes into seven groups the remarkable men who have been the objects of investigations-Statesmen, generals, men of letters, men of science, artists, poets and divines. He sets out from the hypothesis of 100 families studied, modifying his results according to circumstances; for example, when his researches have extended to only twenty, twenty-five, or fifty families, he multiplies his results by five, four or two. Thus he is enabled to institute a direct comparison between the various groups. These results are given in the following table, with the addition of the group already considered -that of the judges. There is no question but that, if we omit columes six and seven, (poets and artists,) which present some singular deviations, we cannot fail to be struck with the resemblance between the figures here compared. pare The impression made by the table will be still more striking, if we comthe first column, that of the judges of the men whose kinships the author has studied more closoly-with the last column, that which gives the averages, that is, with the column which purports the law in numerical terms. The number of families that has served as the basis of the work is about 300 and includes nearly 1000 men of note, of whom 415 are illustrious. The author thinks that, if there is a law, so great a mass of facts ought to bring it to light. This law is given in the last column of table II. The probability that a man of mark would have remarkable kinsmen is: |