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MODERN ASPECTS OF HEREDITY.
By J. C. M. GIVEN, M.D., LOND.
Ir is hardly possible now-a-days to take up any newspaper, magazine or modern novel, or to see any new play, without coming across some allusion to heredity; and as is the fate of all new and much-talked-of theories, a large amount of nonsense is being said and written about this subject. Of late years an immense quantity of facts regarding heredity have been collected, and numerous theories to explain its scope and mode of action have been propounded; and it is the purpose of my Paper to try to put before you some of the most important of these facts, and some of the more reliable of these theories.
The influence of heredity is no new discovery, and the facts that the child resembles its parent, and that the acorn produces the oak and no other form of vegetable life, are as old as human intelligence; but the extent to which our bodily forms, our mental characteristics, and our social ordinances, nay, even our modes of thought and systems of philosophy, are moulded and formed by hereditary influences, and the proportionately small part which education and acquired characters take in this process, is not so well recognised.
Ibsen is probably responsible to a large extent for popularising this subject, and his plays, such as Ghosts, Romersholm and A Doll's House are good examples of the unreliable and loose ways in which scientific facts may be misused in the treatment of social relations by a writer of superficial and inexact knowledge. Of the literary value
of his work I have nothing to say, but one has only to read his plays carefully to see the forced and ridiculous manner he uses the terms and phrases of heredity. It is also worthy of note that Ibsen confines himself to portraying the transmission of bad and disagreeable qualities, and, while none of his characters appears to inherit anything desirable from their parents, they all have plenty of faults, the existence of which is explained by ancestral taints. Zola has also given us a study in heredity in his long series of novels depicting the history and development of the different members of the RougonMacquart family, culminating in Dr. Pascal, the last of the series. His methods and applications are more reliable and less exaggerated than Ibsen's, but he, too, seems determined to paint most prominently the disagreeable side of the picture.
We have not far to seek for the cause which gave this impetus to the study of heredity, when Darwin, and independently of him, Wallace, formulated his theory of the origin of species, the chief factor in this process was heredity, modified by natural selection. Thus the necessity for collecting data on this subject, and determining its scope became evident. The researches of Galton, who was one of the earliest in the field, are numerous and interesting. He examined the family histories of different series of individuals who were specially gifted, either intellectually or physically, in order to ascertain to what extent their children retained any of the parental qualities.
Thus, he took the judges of England from 1660 to 1865, this series included 286 judges, whom we may acknowledge to be a peculiarly gifted class of men, seeing the process of selection they have to go through before
attaining that position. Of this series of 286 individuals, 109 were found to have relatives who had attained eminence in some line or other, these relatives numbering 124. Again, taking the most eminent of this same series, namely, the lord chancellors, who were 30 in number, we find that 24 of them had eminent relatives. Thus, while 36 per cent. of the whole series of judges had eminent relatives, 80 per cent. of the lord chancellors had them. Again, out of the 286 judges more than one in every nine was father, son or brother to another judge, and other high legal relationships were even more common. Surely these figures show that the peculiar type of ability that is necessary to a judge is often transmitted by descent. But the eminence of their relatives was by no means confined to the practice of law, as among them we find such names as the great Duke of Marlborough, Lord Clive, Coleridge, Cowper, Waller, Herbert, Milton, Fielding, Maria Edgeworth, Gibbon, Dr. Harvey the discoverer of circulation of the blood, Sir Benjamin Brodie the surgeon, and Copley the painter.
It might be urged against such a series that the advantages of family influence would be so strong that relatives would rise to positions which otherwise they could not attain. I do not think this objection is valid, ast important and responsible positions are not filled in such large numbers, in this country at all events, by incompetent men; and, as an example of the small influence which environment and social advantages have in causing men to rise to eminence, Galton mentions the fact of the very rare occasions in which the distant relatives, or individuals not connected with them, who have been adopted by the Popes, have risen to important positions, although this practice of nepotism, which was common in order to supply the place of offspring with high Roman
ecclesiastics, placed the adopted individuals in positions most favourable to their becoming eminent.
By following up the same lines of result in other groups of individuals, among musicians, scientists, literary men, and athletes, the same results were obtained all round, and in order to get a series which he could not be suspected of selecting as being favourable to his purpose, Galton took the series of eminent men put down by Auguste Comte in the calendar which he drew up for his religion of humanity. After excluding a few such as Buddha, Homer and St. Paul, about whose relatives we know absolutely nothing, he found no less than 50 per cent. of them to have had distinguished relatives.
The Bach family* was a good instance of the transmission and perpetuation of a special form of ability, namely, music. This family began in 1556 and passed through eight generations, the last known member of it being chapel master to the Queen of Prussia, in 1845. The founder was a baker in Presburg, who amused himself in his spare time with singing and playing, and from him sprang a crowd of musicians who spread over Germany for two centuries, some being composers, and some performers, and nearly all of them organists and church singers; when they became too numerous to live together and had to disperse, they agreed to unite on a fixed day once a year, this custom being preserved among them up to the middle of the eighteenth century, sometimes 120 persons of the name of Bach being present at the same time.
The Titians again were a well known race of painters, producing ten painters of great ability in three generations.
Taking these and similar facts together, Galton calcu*Lombroso, The Man of Genius.
lated that the chances of kinsmen of illustrious men being or becoming eminent were, in the case of a father, 1 to 6; of a brother, 1 to 7; of a son, 1 to 4; and of a first cousin, 1 to 100. He also found that the chances of kinsfolk through female lines were much less than through male lines, namely, rather less than half; for instance, the chances that the cousin of an illustrious man might rise to eminence, supposing him to be a cousin on the mother's side, are less than half what they would be if he were on the father's side. Thus the Chinese, who reward and honour the parents of children who have proved themselves successful and accomplished, instead of the individuals themselves, appear to know where the real merit lies.
We see from such data as these that the facts of heredity are capable of a much more accurate statement than is generally supposed. Indeed, we might almost say that, given all the peculiarities and qualities of a man's relatives and ancestors, it would be virtually a matter of mathematical calculation to give his component parts, just as a chemist could tell the exact composition of an elaborate carbon compound by knowing the molecular weights and combining capacities of its different elements.
It is a curious fact that colour-blindness is nearly twice as common among quakers as among any other class of men; the proportion being 5.9 per cent. among quakers, and 3.5 per cent. among others. This sect was founded a few centuries back by a body of men who considered that the fine arts were worldly dross, and were presumably deficient in artistic sense, and perhaps in colour appreciation. They closely intermarried among themselves, and hence the natural deficiency was perpetuated and intensified. It is true that Dr. Young, who formulated Galton, Human Faculties.