Popular Science Monthly/Volume 27/May 1885/Can Man Be Modified by Selection?
By W. K. BROOKS.
THE certainty and rapidity with which our domesticated animals and plants may be modified in any desired direction by selective breeding must be regarded as a reason for believing that, if it were possible to pursue the same course with man, the human race also might be rapidly improved in the same way. It is difficult to prove this, for we are almost entirely removed, by our control over Nature and by our artificial life, from the influence of natural selection; and, as we can not dictate to men and women whom they shall marry, we can not bring about a union of those with the same congenital characteristics, or propagate for a number of generations a peculiarity which it is desirable to perpetuate and intensify.
There is reason to fear that our freedom from the influence of natural selection may lead to the degeneration of the race unless some way to supply its place is discovered and adopted; and the first step in this direction is to prove by actual experiment that the race can he modified by selection like any other species of organism.
The researches of Professor Bell, which show that a race of deaf-mutes is actually growing up in the United States through an unfortunate application of the law of selection, therefore have a very great scientific value, which is entirely independent 'of the warning they give of a danger which threatens us.
In the paper which is quoted above he renders the community an important service by pointing out this danger; but it seems to me that the chief value of his work is not in this direct practical bearing, but in the convincing proof which he furnishes to show that the law of selection does place within our reach a powerful influence for the improvement of our race, for, as soon as the truth is borne home to all men by facts like those which Professor Bell has brought together, some effective means of applying it to mankind will certainly be devised.
Mankind will not submit to any direct interference with personal liberty; but, if it is true that desirable characteristics can be perpetuated and developed by selection, indirect methods of influencing the choice of husbands and wives could undoubtedly be devised and employed.
If all the children which exhibit the desired peculiarity could be brought together as early as possible, and could be made to live together during their youth, carefully guarded from the possibility of making acquaintance with any other children, and if this restriction could be continued through the period when acquaintances and friendships and attachments are most easily established, this would be a great step toward selective breeding; for all the children with the desired peculiarity would become intimately acquainted with one another, while they would have few outside friendships. If, after the children had grown up and become scattered, they were encouraged to hold periodical reunions for promoting social intercourse between them in adult life, and if they were provided with newspapers and periodicals of their own, which should make a specialty of "personals" relating to them, giving a full account of their conventions and reunions, and keeping their readers informed of all their movements, their employments, their marriages, deaths, etc., the chances of intermarriage among them would be greatly increased.
If they were taught to speak and think in a language of their own, and were furnished with a literature of their own in this language, they would be very effectively cut off from intercourse with outsiders, and would be compelled to look to their own numbers for their companions and acquaintances; and there can be no doubt that, if all these influences were employed together generation after generation, they would soon lead to the establishment of a race sharply marked off from the rest of the world by the excessive development of the characteristic upon which the selection was based.
If the selection were a wise one, the result would be to the benefit of mankind; but the result would follow just as surely if an injurious peculiarity or a defect were made the basis of the selection, for a natural law produces its effect, whether it is applied wisely or unwisely.
Professor Bell points out that our system of educating the deaf brings all these influences to bear, and that the means which have been adopted by philanthropists and others from the noblest and purest motives to ameliorate the condition of the deaf and dumb are unfortunately the most complete and efficient methods which it is possible to employ for inducing deaf-mutes to marry deaf-mutes, and that it would be difficult to devise a more certain means for increasing the number of unfortunate persons with this infirmity, and for producing by selection a deaf variety of the human race.
We separate them from other children as early in life as possible, taking them away from their homes and placing them by hundreds in institutions where they are isolated from early childhood to the commencement of adult life. Each deaf person is therefore intimately acquainted with nearly all the others of his own generation, while there are few opportunities for the formation of congenial and lasting intimacies with outsiders. The graduates of the institution organize themselves into societies or conventions for the promotion of social intercourse in adult life, and these societies are to be found in all large cities, in rooms where they meet for social intercourse, and for religious worship. They hold State and national conventions, which are attended by deaf-mutes of both sexes from all parts of the country, and they publish newspapers and periodicals of their own which are filled with personal items.
They are taught a special language which is as different from English as French or German or Russian, and they learn to think in the gesture-language, so that English is apt to remain a foreign tongue, while they often write in broken English as a foreigner would speak, so that they are in a great measure cut off from all of our literature except its very simplest forms, and they have imperfect sources of information upon topics which engage the interest of the rest of the community, such as social and political matters.
Although there is no compulsion or infringement of personal liberty, all these influences combine to induce deaf-mutes to select for their partners in life persons who are familiar with the gesture-language, and with whom they have been thrown from childhood. We have, therefore, adopted most of the means which tend toward the formation of a deaf-mute variety of the human race, and time alone is necessary to accomplish the result; but there are still other means which might be employed to hasten it. Professor Bell says that, with this end in view, we might attempt to formulate some plan which should lead the deaf children of deaf-mutes to marry one another instead of marrying deaf-mutes who have not inherited their deafness, or to marry hearing persons belonging to families in which deafness is hereditary. If, for instance, a number of the large deaf-mute families of the United States were to settle in a common place so as to form a community largely composed of deaf-mutes, then the deaf children born in the colony would be thrown into association with one another, and would probably marry in adult life or marry hearing persons belonging to deaf-mute families, and each succeeding generation of deaf-mutes would increase the probability of the deaf-mute element being rendered permanent by heredity; and we might anticipate that a very few generations would suffice for the establishment of a permanent race of deaf-mutes with a language and literature of their own.
Plans for the formation of such a community of deaf-mutes have many times been discussed by the deaf-mutes themselves, contributions of money for the purpose have been publicly offered, and it has even been proposed to procure the enactment of laws to secure the descent of the land and other property in the deaf-mute line alone, so that the hearing children would be led to leave the community. A colony of this sort has even been founded in Manitoba, and twenty-four deaf-mutes with their families have already arrived from Europe and have settled upon the land, while more are expected this year.
The analogy of all other organisms would lead us to expect that, with all these selective influences at work, the number of deaf-mutes should increase rapidly, and the interesting question, "How far do the facts justify this opinion?" at once presents itself, and we ask, first, whether deafness is hereditary; and, second, whether it is true that many deaf-mutes marry; and, third, whether our system of education does lead those who marry to select deaf-mutes as their partners; and, fourth, whether deafness is more frequent among their children than it is in the community at large.
If the published records answer all these questions in the affirmative, it is clear that, however much the present system may appeal to our sympathies, it is neither the best one for the interests of the whole community, nor the best for the deaf themselves, since it tends to increase the evil which it is designed to alleviate.
Few of the institutions publish any record regarding the relatives of pupils, but the records of the American Asylum, at Hartford, Connecticut, show that, of 2,106 pupils admitted to that institution, 693, or nearly 33 per cent, were known to have deaf-mute relatives, and in the majority of these cases the pupils have more than one relative deaf and dumb, while in a few cases as many as 15 deaf-mute relatives are recorded. The report of this institution for 1877 shows that
That this is not peculiar to the pupils of this particular institution, and that it holds true of deaf-mutes in general, is shown by the following table, compiled from the records of six institutions:
The table shows that, among 5,823 deaf-mutes taken from different parts of the country, 1,719, or 291⁄2 per cent, are known to have had deaf-mute relatives, and that this is due to the influence of heredity is well shown when we contrast those who were born deaf with those who had afterward lost their hearing. Many of those who lose their hearing by accident or disease have no hereditary tendency to deafness, but a considerable number of those who lose their hearing at some time after birth are born with an hereditary predisposition to deafness. If, therefore, we contrast the congenitally deaf with those who have become deaf, we should expect the latter class to have a much smaller percentage of deaf relatives than the former class, but a greater percentage than the community at large.
Professor Bell has compiled the following two tables from the one which is given above, and they show that, while only about 13 per cent of the pupils which were not born deaf have deaf relatives, more than 54 per cent of the congenitally deaf pupils are recorded as having such relatives:
Table II.—Proportion of the Non-congenitally Deaf who have Deaf Relatives.
Table III.—Proportion of the Congenitally Deaf who have Deaf-Mute Relatives.
These tables show that, of 2,262 congenital deaf-mutes, more than half are known to have had deaf-mute relatives, and that, even in the case of those pupils who become deaf from apparently accidental causes, more than 13 per cent had other members of their families deaf and dumb.
In answer to the second question, Do deaf-mutes marry? Professor Bell gives a number of tables, one of which shows that, out of 1,259 pupils at the American Asylum and the Illinois Institution who were born before 1840, 571, or nearly half (45·4 per cent), are recorded as married. The records for later years show a much smaller number of marriages in proportion to the total number of pupils; but this would necessarily be the case, because most of them are as yet children.
In order to determine how many of this 45 per cent of deaf persons who marry chose deaf-mutes for their partners, Professor Bell has compiled the following table from the records of five of our largest institutions for the deaf and dumb:
Table IV.—Proportion of the Deaf and Dumb who marry Deaf-Mutes.
This shows that nearly 80 per cent of the deaf-mutes who marry at all marry deaf persons; but it does not follow that 80 per cent of the marriages were between deaf persons, for it is probable that nearly all of the 856 pupils who married deaf persons married pupils, so that there may possibly have been only 428 weddings; while the 1,089 minus 856, which equals 233 who married hearing persons, may represent only 233 weddings, so that, out of 661 marriages, only 428, or 65 per cent, may have been between deaf persons, but even this is an alarming frequency, if it is true that the children of such unions are predisposed to deafness.
If it is true that our system of educating the deaf is responsible for the number of marriages between deaf persons, we should expect to find these marriages increasing in numbers, and Professor Bell has compiled from the table above quoted the following table, which shows that this is the case:
These two tables show that the tendency of deaf-mutes to select deaf-mutes as their partners in marriage is very pronounced, and that it is much more developed now than it was during the early half of the century, and that it is steadily increasing.
Thus there is every indication that this process of selection will go on from generation to generation, and that a large proportion of the deaf children of deaf parents will themselves marry, and that, of those who marry, the majority will marry deaf-mutes.
If it is true that deafness is hereditary, this can have only one result—the increase of deafness.
There are very few reliable statistics regarding the number of children born to deaf-mutes, or the proportion of deaf children, but Dr. Turner, formerly the Principal of the American Asylum, stated, in 1868, that statistics carefully collated from records kept of deaf-mutes, as they have met in conventions at Hartford, show that in eighty-six families, with one parent a congenital deaf-mute, one tenth of the children were deaf; and in twenty-four families, with both parents congenital deaf-mutes, about one third were born deaf.
In 1854 Dr. Peet, the Principal of the New York Institution, said that, of all the families of which he had records, "about one in twenty have deaf-mute children where both parents are deaf-mutes, and about one in one hundred and thirty-five where only one is a deaf-mute; and that the brother and sister of a deaf-mute are about as liable to have deaf-mute children as the deaf-mute himself, supposing each to marry into families that have, or each into families that have not, shown a predisposition toward deaf-dumbness"
Our author has attempted to trace out from the scanty records the history of certain families in which deafness is hereditary, and he has expressed the facts in a number of graphic diagrams, two of which are here reproduced.
THE HOAGLAND FAMILY, OF KENTUCKY.
In this family nineteen out of twenty-six descendants were deaf, and it is interesting to note that, although one of the members of the family was a hearing person, and married a hearing husband (Reed), their two children and three grandchildren were all deaf. One of the descendants, No. l, was deaf and married a deaf-mute, but their five children all hear. No one could refer to this branch of the family as a proof that deafness is not hereditary, however.
the hoagland family, of kentucky.
The diagram on the following page shows the genealogy of the Fullerton family, of Hebron, New York:
Fullerton had seven children, all deaf and dumb. There is no further information about six of these children or their descendants; but the seventh, Jane Fullerton (1), married Sayles Works (2), who was also a deaf-mute, and all their six children were deaf and dumb. No information was obtained regarding the descendants of these six children.
Those persons who are not familiar with logical reasoning will point to married deaf-mutes with hearing children as proof that such marriages are not to be condemned; but, in order to prove that deafness is hereditary, it is not necessary to show that all the children of deaf parents are deaf, but only that the number of deaf children, as compared with the hearing children, is greater than it is in the community as a whole, and this fact is proved beyond question by the statistics.
The census returns show that there are 33,878 deaf-mutes in the country, or that one person out of every 1,500 is deaf; or that, out of each 1,500 children who are born, 1,499 retain their hearing throughout life, while only one is deaf.
If deaf children are no more numerous in the families of deaf parents than they are elsewhere in the community, only 23 out of the 33,878 deaf-mutes should have deaf parents; but we have a record of nearly ten times this number, for Professor Bell states that, although
THE FULLERTON FAMILY OF HEBRON, .
only thirty-five of the fifty-eight institutions of the country have sent replies to his queries, the returns from these thirty-five show that no less than 207 deaf children of deaf parents have been admitted as pupils. Deaf children are, therefore, at least ten times as numerous in families where the parents are deaf as they are in the community at large, and it is impossible, after reading Professor Bell's paper, to doubt 1. That deafness is hereditary; 2. That, of the deaf persons who marry, nearly all select deaf partners; 3. That their children are especially liable to deafness; and, 4. That the number of deaf-mutes who marry deaf-mutes is increasing, and that our educational system fosters this tendency, and is to a great extent responsible for it.
So far Professor Bell's conclusions seem to be unanswerable, and there is no room to doubt that the means that we have adopted for the amelioration of the conditions of the deaf have actually tended to increase the evil they were intended to diminish.
The question whether this can be avoided, while the system as a whole is retained, is one upon which there may well be a difference of opinion; and the fact that the publication in 1868 of a paper on "Hereditary Deafness," by the Principal of the American Asylum, the Rev. W. W. Turner, has been followed by a decrease in the number of marriages between the pupils of that institution, seems to show that it may be possible to accomplish much by repressive influences. Our author believes, however, that the defect is inherent in our system, and that a complete change is necessary; and that the segregation of deaf children in institutions, where they are kept by themselves, really lies at the root of the matter; and that the grand central principle, which should guide us in our search for preventive measures, should be the retention of the normal environment during the period of education. The direction of change should therefore be toward the establishment of small schools and the extension of the day-school plan. The average cost of the education of a deaf child in an American institution is $223.28 per annum, and a small day-school could be maintained at no greater cost, although the parents would be compelled to furnish, in addition, the industrial training which is now provided by the State; but this would give no concern, for so many deaf-mutes are now earning their livelihood by trades which are not taught in the institutions as to demonstrate the practicability of apprenticing deaf-mutes in ordinary shops.
The employment of the gesture-language and lack of articulate speech are efficient elements operating to separate deaf-mutes from hearing persons, and Professor Bell advises that all deaf pupils should receive instruction in articulation and in speech-reading. In the schools of Europe more than 65 per cent of the deaf and dumb were, in 1882, receiving efficient instruction in this way, and were taught to speak and understand the speech of hearing persons, while in our institutions 4,241 pupils received no instruction whatever in articulation, and only 886, or 14 per cent, were under oral instruction.
The question whether these remedies are the best and most practicable ones or not may safely be left to the judgment of the able men who have devoted their lives to the subject; but all those whose sympathies for this unfortunate class are strongly excited must bear in mind that the interests of the whole community are also to be considered, and no one could, in the interest of humanity, or even in the interest of that small portion of the human race most directly concerned, advocate measures which lead to the perpetuation and increase of the evil.
Whether we approve of Professor Bell's recommendations or not, all persons, those who hear as well as those who do not, must feel that he has done good service to the community by calling attention to the danger which now attends our system, but his paper is far more than a warning: it is a promise, and its direct practical bearing is a very small part of its value, for the facts which he has brought together prove that man can be modified by selection as readily as any of our domesticated animals or plants, and that increased knowledge will ultimately enable us to bring about rapid improvements in our race.