CONSUMPTION AND MARRIAGE.

New Zealand Mail, Issue 1774, 7 March 1906, Page 66

CONSUMPTION AND MARRIAGE.

Writing in the “Daily Chronicle'” C. W. Saleeby says:—l have been asked to discuss an extremely difficult an cl important subject. Suppose there bo a definite family history of consumption What is the duty as regards marriage of the members of that family, assuming that they themselves, at the time when the question ie raised, are, so far as they knoiv, in good health? The duty referred to is obviously that towards posterity, and we* shall not concern ourselves here with the question of duty in so far as it refers to the possible pfartner. If the fact of our duty towards the future had bedn as clearly present in the minds of our forefathers as it is in cure, they would have returned an answer to this question, at once unqualified and distressing. For them consumption was an hereditary disease, probably of the nature of a premature degeneration of certain tissues, which conspicuously ran in families, and to which the children of a consumptive parent or consumptive parents, and also those persons possessed of a certain shape of chest-—the phthisical chest—were almost inevitably foredoomed. If, then, the question of duty towards upborn children was to be entertained, plainly such persons should not many. For the sake of the present argument, we may assume that there is no third possibility; though the fact of that possibility may be of the utmost importance in this, and in may other instances. Its nature has lately been defined by the Bishop of London for the benefit of all who might not be aware of it. IMMUNITY. But now we know very precisely that there is one essential factor at any rate, in the causation of consumption, which was unsuspected by our fathers, and that, as every reader is aware, is the tubercle bacillus. Whether or not there be any other essential factor, there is at least this; and, furthermore there are on record only one or two instances—out of posable hundreds of millions —of children being, at birth, already preyed upon by this bacillus. In the first place, then, whoever is to suffer from consumption must become Infected by the bacillus. In this as in the case or every other infectious disease, however, there is a second factor. If the feed is to' grew, it must fall upon suitable soil. The tubercle bacillus is practically omnipresent, in cities, at any . rate. Everyone of us has frequently swallowed it in milk; we have all inhaled it times Without number. The seed is everywhere sown, yet five out of six of us do not die of tuberculosis. There is thus raised the question of immunity and susceptibility. Why are some of us susceptible but some immune? Now, in the case of a large number of diseases there can be no question that immunity and susceptibility are matters of inheritance, and, we may practically say, of nothing else. If you are one kind of sheep and are inocuiated with anthrax bacilli, you will suffer; but if you are another kind of sheep you are immune. If you are one kind of man, you will take measles in your infancy, but will recover; if you are another, for instance, a South Sea Islander, you will die, measles being as fatal to you as plague or cholera, to us. Similarly with, many more diseases, racial differences in this respect having been explained by Dr. Archdall Reid as the result of past experience of the disease which by natural Selection, has weeded out the susceptible stocks, and thus, in certain cases, has evolved races that are more or less completely immune. INHERITED TENDENCIES.

Now, in the case of tuberculosis, I. am bound fiorroAvfully to admit that, in some measure, the same holds true, so far as the great racial differences are ooncerned. The terrible experience ot the Red Indiana is sufficient proof of this. Nevertheless, this disease un-

questionably differs greatly from most of the others that have been mentioned, . and for this reason —that immunity or susceptibility are determined, to an exceptional degree, by the general state of the bodily, health. - That is why consumption is in general a disease of Of the lower classes in this country, the fewer victims of the upper classes paying the penalty for the indifference of their class to the misery beneath them. It is a difficult question to de-

termine, but it is probable that whereas if you are inoculated by the bacilli of plague you will certainly develop ■plague, yet, if you are inoculated with tubercle bacilli you may or may not suffer ; the result being determined (as well as by the virulence of the particular bacilli in question) more by the state of you general health at the time than by any property inherited and inherent in your tissues. That is to say, so far as infection -with the tubercle bacillus is concerned, you are better to be in thoroughly good health breathing fresh air and' living a sane life, though your parents died of consumption, ‘ than to have a . clean bill so far ash your family'history is concerned, but to breathe dirty air and be in poor health. It is perhaps rash to make this statement, and I am certain that at cannot be regarded as... established, but the evidence inclines us, to the

view Jetezt in determining one’s degree of immunity to the tubercle bacillus, environment is of more importance than heredity; it is assuredly ot greater relative importance than- in the cases of inert other diseases.

There wj no question whatever that cases of supposed inheritance of tuberculosis have been wrongly interpreted, even since the establishment of the germ theory. Father and son alike suffer, but so also, only too often, do husband and wife, and the factor which explains the latter case murt not be forgotten in the former. It is increased risk of infection. Tuberculosis is by no means a very infectious disease. But is has been clearly established that countless eases of the supposed hereditary transmission of the liability to tuberculosis are capable of the simpler explanation, as consequences of excessive exposure to infection. A LIMITED RISK. If I am asked in general terms my opinion regarding the marriage of the insane, then following all who have studied the subject, I am bound' to assert with the utmost emphasis that, except in certain classes of cases which can be distinguished, it is a wicked and abominable and brutal thing for such persons, and for many other defective or degenerate or diseased classes of humanity, to have children. There is conspicuously one infectious disease, due to a microbe recently discovered, which renders the parenthood of its victims a crime of the very blackest; but for the reasons I have already advanced, it is impossible to return a similar answer in the case of tuberculosis.

In the first place, Ave have seen that the children of consumptive parents contain no tubercle bacilli at birth. We have seen, on the other hand, that in all probability such children are more liable, others things being equal, to admit and entertain this bacillus than children of non-consumptive parents. But, on the other hand, we have seen that, in the case of this disease, as in the case of certain others, the state of the general health is a factor of particular importance, and also that another explanation is possible in a very large number of coses of apparent transmission of susceptibility. , My opinion will, I think, be supported by the highest authorities Avhen I say, professed advocate of Eugenics though I be, that the marriage of persons having a consumptive family history connot te forthright condemned. Under proper conditions, such as those under which we should all live, these persons and their children run a risk of consumption which is l probably not very much greater than that of their sensible neighbours, and is much less than the ridk run by the sort of people—still extant, I hear—'who sleep with thdir bedroom windows shut. But if some of us are to marry and some are not, I would rather, in general, that those who have had such a bad family history remained in single jlessodness. I say, in general, because follower of science though I be, I am not quite such a fool as to forget that circumstances alter cases!

In a subsequent issue of the same journal Professor Karl Pearson of University College, London, comments on the above art!die as follows: — In the article by I>r. Saleeby, in your issue of to-day, January 15, occur the following words: —"My opinion will, I think, be supported by the highest authorities when I say. . that he marriage of persons having a consumptive family history cannot be forthright condemned. Under proper conditions, such as those under which we should all live, these persons and their children run a risk of consumption which if* probably not very much greater than that of their sensible neighbours, and is much less than the risk run by the sort of people—still extant. —who sleep with their bedroom windows shut.” In the present state of our knowledge of heredity in man, I venture to assart that these words are!, at any rate in my opinion, little short of criminal, and this even if we admit that only the tubercular tendency is inherited.

The columns of a daily newspaper are not the proper place to discuss the statistics of consumptivity in stocks, but I think it would l be as well if Dr. j'aleeby, instead of using vague phrases, would put on record the widenoe upon which his statement is based. It is not in accordance with statistical evidence in my own possession, and the- oonstlant open-air life, riiicih is to some extent only, a prevention of tubercular development, is largely incompatible with active useful citizenship. Those who thoughtlessly inflict even a tendency to tubercular disease on their children are largely handicapping their children’s possiDiliities in life, and are thus acting in a manner diametrically opposed to the national welfare. Any light-hearted encouragement, such as Dr. Saleeby gives, to such anti-social conduct, seems to mo at the present time deporable, and I have ventured on this ground to use oven a stronger term.

KARL PEARSON. Biometric Laboratory, University College. London.

To this Dr. Saleeby retorts:— Professor Karl Pearson accuses me of using words which, in his opinion, are “little short of criminal” —a term which, as he remarks, is stronger than “deporable,” also employed in his ©ttcr. He accuses me also of giv« “light-hearted encouragement to antisocial conduct.” His language, and especially his use of the word lighthearted—as inapplicable as any in the dictionary—would grieve me were it not that, as a student of Professor Pearson’d interesting and important letters in the “Times,” —wdiich I always cut out—l am now familiar with his controversial vocabularly, in wdiich “criminal,” after all, means little more than, say, “unwarranted,” or “unverified.

1 I could refer Professor Pearson to twenty places in which I have declared hat no statistics can nowadays be interpreted without the aid of his methods, to which I attach the utmost importance. Hence, I look forward to the publication of the statistical evidence /hich he says lie has in his “own possession.” At present Ave are very 'much in need of statistical evidence, rigidly interpreted by Professor Pearson’s methods, Avhich will demonstrate the inheritance of what lie calls consumptivity—the factor of exceptional exposure to infection being rigidly excluded. Having described the expression of my opinion as little short of criminal, Professor Pearson obviously has laid it upo'n him to justify his Avords (avo Avill assume, of course, that criminal means' unAva-rranted). If he does sc, he may count upon me to give all the publicity I can to thei fact, and to quote it as one more triumph for him and for biometrics, as I have already done in the case of his valuable contributions to the subjects of antityphoid inoculation and of mental inheritance in man.

I find that three times in my article I expressed the belief which Professor Pearson holds SO' strongly, that the tendency to entertain the tubercle bacillus is transmissible. My point was that, iu this disease, the part played by heredity, as compared Avith that played by environment, is relatively small; thus, if the environment Avere- as unimportant as Professor Karl Pearson thinks —an opinion Avhich seems to me urnvarranted, or, as he would say criminal—it would be difficult to explain the fact that tuberculosis fn ds the overAvhelming majority of its victims amongst the poorer classes, Avhose environment is so bad. If heredity Avere the preponderating factor, we should expect natural Selection to assert itself, and the disease rapidly to become extinct in virtue of its own destruction of the susceptible stocks. The disease is diminishming, but its diminution is not determined, as on Professor Pearson’s theory it should be, by the completeness Avith Avhich susceptible stocks are exterminated, but by environmental conditions, the curves of overcrowding and of tuberculosis slioaving a very close, correspondence.

•' flhe foremost medical student of statistics in this country is now preparing a small volume on tuberculosis, designed primarily for the intelligent layman. I' earnestly hope that Dr. Pearson will soon publish the statistics to Avhich he refers, so that the writer may have the benefit of his conclusions.

One phrase in Professor Pearson’s letter explains, I believe fully, our diffenence of opinion. It is this:— Even if we admit that only the tubercular tendency is inherited.” Now that certainly has to be admitted; indeed, I was criticised the other day for asserting that in one or two cases—l believe there are two on record, but there may be more—the tubercle bacillus has been found in the new-born child. The whole point is that only the tendency is inherited, and therefore, that, before the importance of such inheritance can be estimated, it is necessary to' exclude the factor of exceptional exposure to infection, which obviously prevails in an enormous number of oases whore children are born to consumptive parents. The question is whether, if another child were substituted for heirs, and similarly exposed to tlheir dried expectroation and the like, it would not be almost as liable to the disease as their own child would have been. Gan Professor Pearson answer this question in the final and invaluable fashion in which lie has already answered many similar questions? Is the factor of exceptional exposure to infection rigidly eliminated in the statistics which he has in his possession? If not, I submit that his strictures upen me lack in theiri substance that abundant vigour which is so conspicuous in their form.