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Typos — p. 259, n. 3: Sterilitat [= Sterilität]

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Appendix I
The Question of Interval between Births

After we had completed the preceding pages, it was pointed out to us that we might have said more on the question of spacing births and how this is to be achieved without the use of contraceptives, the general implication of our book being that in normal circumstances the natural laws determining the succession of pregnancies will be found adequate to bring about the necessary optimum interval of from two to three years between births without any artificial interference. And we therefore propose to devote a few pages to the discussion of this question alone.
        Much has been said in the preceding chapters regarding what medical men usually term the "optimum interval" between births, i.e. the space of time which should elapse in any healthy family between successive births if the mother is not to be exhausted, and the children are not to be handicapped by having their parent's strength strained during gestation and lactation. And this optimum interval has been variously stated as from two to three years. During this interval the mother is supposed to be able to recover from the claims made upon her system by pregnancy and child-birth, and to be able to complete the breast-feeding of her last child; for it is rightly observed by

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most authorities on this subject that whenever a pregnancy occurs during the period when breast-feeding is still a necessity to the last child, the damage done is threefold — the mother herself is exhausted, the infant she is suckling is deprived of its full share of her strength, and the becoming infant in her womb may suffer injury from the fact that her energies are divided between two exacting functions.
        Now if we add ten months of lactation to the nine occupied by gestation, we get a minimum period of nineteen months, during which a mother may be said to be engaged with her last pregnancy and its consequences. And if we suppose a further pregnancy to occur shortly after weaning, nineteen months — barely two years — will have elapsed between the first and second birth. This, according to the best authorities, however, is not long enough. It is at least five months short of the lowest estimate usually given for the optimum interval. Besides, even if we chose to leave those five months to chance, i.e. even if we relied on the frequent failure to achieve fertilisation, which characterises such a large proportion of the acts of sexual congress in human beings, in order to account for those five months of reproductive inactivity in the female, what is to guarantee that the woman who has borne a child and who is suckling it shall not conceive before her ten months of lactation are over?
        In answering this question there are various matters which will have to be considered.
        In the first place, owing possibly to the fact that sexual intercourse among human beings does not take place during the menses, 1 or for other reasons which

        1 See Dr. P. W. Siegel, op. cit., pp. 50–1.

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have not yet been investigated, the congress of the sexes, as we have hinted above, does not, as in animals, almost invariably lead to fertilisation. The figures collected by Matthews Duncan from the birth registers of Edinburgh and Glasgow, for the year 1855, i.e. before Birth Control and a knowledge of contraceptive expedients were generally and widely known — according to which he discovered that out of 4,447 women married in 1855, only 643 had a child within the first year, while 3,172 had a child within two years 1 — are sufficient to show that immediate fertilisation, when conditions for regular normal intercourse are most favourable, must be the exception rather than the rule; for we must bear in mind that the figures for births of the first child in the first year of marriage are greatly swelled by ante-nuptial conceptions. 2 Ansell, who examined 6,035 cases, certainly before 1885, found the average interval before the first birth sixteen months. 3 And

        1 Fecundity, Fertility and Sterility (2nd Edition 1871), pp. 26, 28. See also p. 131, where Dr. Duncan estimates that in fertile marriages seventeen months generally intervenes, before the birth of the first child. This is based on an examination of 3,722 cases taken from the Edinburgh and Glasgow Register.
        2 See on this point Dr. C. J. Lewis (Natality and Fecundity, 1906, pp. 85, 86, 94, 95). Dr. Lewis reminds us that owing to ante-nuptial conceptions, the figures covering a period of two years after marriage are more reliable than those referring to the first year only.
        3 Kisch, Die Sterilitat des Weibes, p. 106. See also Dr. R. A. Gibbons, Sterility in Woman, p. 20, in which he quotes Pfannkuch as estimating an interval of twenty-six months before the first delivery in women marrying before the age of 20, and twenty months in women marrying after the age of 20.

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Dr. E. H. Kisch, with figures collected before 1885, found that out of 556 fruitful marriages, the first delivery took place

In more
10   months
11 to 15  "
16 to 24  "
2 to 3 years
 than 3 years
after marriage in
    "        "
    "        "
    "        "
    "        "
 156 cases.
 199    "
 115    "
   60    "
   26    " 1

        It is true that, as far as we can judge, no account appears to have been taken of still-births and miscarriages in these figures, but even if we suppose that these made a reduction of 7 per cent. in the proportion of the firstborn, 2 we should still have a period of time considerably longer than would justify us in assuming

        1 Sexual Life of Woman, p. 367.
        2 The amount 7 per cent. is suggested by Dr. G. F, Still's "Ingleby Lectures," reported in the Lancet of October, 1927, in which this medical man says that in a series of 800 live-born children, it was found that the inclusion of miscarriages and still-births made a reduction of 7 per cent. in the proportion of the firstborn. (See Lancet, October 15, 1927, p. 797.) Figures confirmatory of this are not obtainable from English registers, as still-births are not recorded. But if we take the still-births recorded in Germany over the years 1841 to 1899, we find them varying between 3.3 per cent. and 4.1 per cent. of the total born, and remaining chiefly about 3.7 per cent. So that Dr. Still's figure cannot be very far wrong, although it includes miscarriages and is derived from a series of only 800 live-born children. Dr. Gibbons, quoting Dr. A. Routh (op. cit., p. 23), says that there are 11 miscarriages and still-births to every 100 live-births in England and Wales, the proportion of miscarriages to still-births being as four to one. But this seems a little excessive, and should be compared with Priestly's figures on the same page, which give a much lower percentage. Thus Dr. Still's 7 per cent. cannot be far wrong.

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that fertilisation in human beings followed intercourse with the same clockwork regularity as it does in most animals (cats and dogs, mice and rats, for instance, of which the present writer has had some experience). It therefore seems justifiable to assume that normally regular intercourse after the weaning of the first, second, third or fourth child would not and does not in the majority of cases lead within the first few months to a further pregnancy, and indeed only does so exceptionally. If, therefore, we suppose that an average interval of five months or more elapses after the ten months of lactation, before a further pregnancy occurs, we arrive at our lowest estimate for the optimum interval between births, which is two years. Truth to tell, however, the interval in practice is frequently longer, and thus we find Duncan, Gaehlert, and Hegar, giving twenty months, 1 twenty-four to twenty-six months, and twenty-six months respectively, 2 as the normal interval, with no mention of contraceptives; while, as we have seen in the preceding pages, 3 where there is no evidence of contraceptives being used, and among that class in which it is generally admitted, even by birth-controllers themselves, that contraceptives are not generally used, the normal interval between births was found by Dr. Gamgee in large families to be two years and two months (including miscarriages and still-births), by Sir John Robertson (who does not mention miscarriages and still-births) to be on an average 3.2 years, and by Dr. Siegel to vary from two to four years,

        1 Op. cit., p. 107.
        2 Kisch, Sexual Life of Woman, p. 367.
        3 See pp. 91, 145, 152, 153.

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according to the time that had elapsed since marriage. 1
        From these data alone it would appear to be justifiable to conclude: (1) That while there appears to be some influence at work during lactation to make conception at least exceptional, it does not follow, because sexual intercourse is regular, even after lactation, that fertilisation will occur, — in fact the chances are all in favour of some months elapsing before a fresh pregnancy occurs. (2) That even where contraceptives are not used, too frequent pregnancies appear to be prevented by lactation, and by the more or less normal failure of human sexual congress to achieve prompt fertilisation, even when all the conditions are in favour of it.
        This, however, brings us to our second consideration, in regard to the optimum interval — the question of lactation and relative infertility.
        It has long been known, even by the most uncultivated races of mankind, that there exists a kind of antagonism between the functions of the uterus and the mammary glands in the normal woman, so that it is exceptional for conception to occur during lactation. And, indeed, quite apart from the evidence on this point, which can be adduced from the works of anthropologists as well as modern medical men, the very figures we have given above force us to conclude that there must be some such influence at work, otherwise it is difficult to account for the fact that the interval

        1 See p. 145, ante. See also Duncan (op. cit.), pp. 135 and 247, and the Report of the Medical Committee on Contraception (Medical Aspects of Contraception, Hopkinson, 1927), p. 4.

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between births is so regularly sufficient to allow a mother to complete lactation before another pregnancy begins. We are not compelled to accept the view that there is an antagonism between the functions of lactation and conception; all we need to observe is that, in the great majority of cases, some influence seems to be at work during lactation to prevent pregnancy. And this we are compelled to do unless we are prepared to assume: (1) that in all the cases referred to above the couples abstained from sexual intercourse during lactation, or (2) that they used contraceptives.
        In view of the classes and period from which the figures have been derived, however, it is extremely unlikely that sexual abstinence was the cause of the absence of pregnancy during lactation and after; for if sexual abstinence, though possibly desirable during that period, 1 may sometimes be observed by polygynous savages and some of our polygynous aristocrats and commercial and industrial magnates, it is quite certain that in the moral and monogynous classes from which the above data have been drawn, no such rule is observed.
        Neither are we entitled to suppose that contraception has been the cause of the absence of pregnancy; during lactation and after among the couples concerned in the figures given above. For not only are most of the data derived from a class notoriously averse

        1 See Dr. John S. Fairbairn (The Practitioner's Encyclopædia of Midwifery and the Diseases of Women, 1921, p. 59): "There can be no doubt that marital continence for the whole period of pregnancy and during the lactation time is the ideal relationship to be arrived at by the parents who wish to lead a healthy married life and to have strong and well-formed children."

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from contraceptive practices, not only is there no evidence of contraceptives having been used in the cases examined to form the averages; 1 but the lowest figures given for the normal average interval (twenty months) are taken from Dr. Matthews Duncan, who was collecting data in Scotland in 1855 — long before, that is to say, the general public in Great Britain were made as familiar with contraception as they have been to-day, or could easily obtain contraceptive appliances and expedients. Besides, from an examination of Part II of Volume XIII of the 1911 Census, we find that the period covered by most of the averages quoted, relates to a time when families were notoriously large at least in England and Wales.
        If, however, we turn to the medical experts, to anthropology, and to popular tradition and experience, we find abundant evidence of the fact that there is some interdependence between the functioning of the breasts and the non-occurrence of pregnancy, and that it is exceptional for conception to occur while lactation is being continued. Whether the widespread belief that this is so, and the facts confirming it, point to an actual antagonism between the gestatory and lactatory functions is not important from our point of view. It is

        1 The birth-controllers are inclined to argue that, when no evidence is given of contraceptives not having been used, they are entitled to suspect that they may have been used. But surely, since they are the innovators and the advocates of new and unnatural methods, and on their own showing, the modern Birth Control Movement can hardly be said to have started before 1877, it is incumbent upon them to prove that contraceptives have been used, before they can contest the reliability of such data as we have given above, or cast suspicion upon it.

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sufficient for our purpose that there appears to be ample justification to postulate in all but exceptional cases that lactation is a safeguard against conception.
        Writing on this very point. Dr. G. T. Wrench, whom I have already frequently quoted in these pages, and whose great experience as a gynæcologist makes his opinion particularly valuable, writes as follows:—

"As regards the frequency of child-bearing, it may be laid down that nature has given a good guide in that she prevents conception taking place with few exceptions whilst the child is being suckled. In most countries of the world, the period of suckling stretches over at least two years. 1 Consequently a space of some three years elapses between the successive births of children." 2

        To hear from a Past Assistant-Master of the Rotunda Hospital, Dublin, that "nature" herself has given a good guide in this matter of spacing births without the use of contraceptives, and that she achieves this "with few exceptions" by preventing conception "whilst the child is being suckled," ought to be sufficient for most people's purpose. Nor is the passage quoted significant only in this respect. We shall have occasion to refer to other aspects of it in a moment.
        In his Sexual Life of Woman, Dr. E. H. Kisch reminds the reader that Gaehlert, in giving twenty-

        1 In La Femme Criminelle et la Prostituée (Felix Alcan, Paris, 1896, p. 108), C. Lombroso and G. Ferrero inform us that suckling is prolonged by the Russians and Persians for two years; by the Australians, Todas, Chinese and Japanese, for two to three years; by the Greenlanders, Mongols and Kabyles, for three to four years; by the New Caledonians, for four to five years; and by the Esquimaux, for six to seven years,
        2 Healthy Wedded Life, p. 49.

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four to twenty-six months as the normal and average interval between births, is careful to point out "that in cases in which the child dies very soon after birth, the birth of the next child ensues on the average in 16 to 18 months." 1 And Dr. Kisch adds, "Mothers who do not suckle their children become pregnant considerably earlier, on the average, than those who undertake this duty." 2
        Dr. A. C. Magian, 3 discussing this same problem, says:—

"The average interval between two successive births is about two years, unless a child dies at birth, or lactation is unduly prolonged. In the first case the period is diminished and in the second it is increased."

        Both Kisch and Magian thus appear to expect an interval of shorter duration between the birth of a child which is not suckled for the full term or longer, and the birth of the next child. 4 And Dr. Mary Scharlieb, in her evidence before the Commission of Enquiry into the Declining Birth Rate, 5 said, in reference to women who have a child a year: "I do not think that is often so with the woman who suckles her child as she should do; it mostly occurs with women who do not suckle their children." And, later on, she said, concerning the possibility of conception during

        1 p. 367.
        2 Ibid.
        3 Gynæcologist to the Manchester French Hospital (Sex Problems in Women, p. 170).
        4 See also Iwan Bloch, M.D. (The Sexual Life of our Time, p. 700): "It is well known that during lactation the menstrual periods fail to occur and that fertilisation is exceptional."
        5 See Report, pp. 272, 277.

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lactation, that it was "comparatively rare: a small percentage of such cases occur."
        The evidence from anthropology is overwhelming on this point and enables so careful and scholarly a scientist as Mr. Robert Briffault to write as follows:—

"It may incidentally be noted that the relative fertility of savage as compared with European women, which has been set down in turn to every custom and practice of which European sentiment disapproves, though it cannot be statistically or otherwise associated with any, has one constant cause, namely, the custom of suckling children 'until they wean themselves,' that is, for two, three, and not infrequently five years, or more." 1

        And later on he gives overwhelming evidence from innumerable tribes and races in every part of the world to show that "from two to three years is the most general duration of nursing." 2
        The fact that conception during lactation is rare and exceptional has, of course, been hotly contested by birth-controllers, and they have made the most of recorded exceptional cases in order to destroy the faith of modern people in this natural method of regulating births. They have gone so far, indeed, that they often do not trouble, in quoting cases of too frequent pregnancies, to state whether the women did or did not suckle their children — as if the question had no material bearing upon the circumstance of her exceptional fertility. But while they can hardly contest the anthropological data that are available on this matter, nor question the general validity of the modern scientific claim that conception is rare during lactation, it

        1 The Mothers, Vol. I, p. 219.
        2 Ibid., Vol. II, pp. 391–2.

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should be remembered that, as Feminists, they are not over anxious to press the necessity of breast-feeding on all the women they address, because lactation greatly interferes with that alleged "freedom" which is so very much to the fore among the desiderata of the Feminist Movement.
        It is not claimed here that lactation can in every case be relied upon to prevent conception, 1 nor, among the authorities quoted, have we been careful to select experts who are known to be opposed to Birth Control. Indeed, to the best of our knowledge. Dr. Wrench, Dr. Magian, and Dr. Bloch, far from being opponents of Birth Control, or even anti-feminists, are either quite neutral or else actually in favour both of preventive intercourse and Feminism; while, as an anthropologist, Mr. Briffault's bias is distinctly feministic. It is true that Dr. Scharlieb and Dr. Kisch are opponents of Birth Control; but there is no more reason to suppose that they have been biased in their scientific judgment by this fact than to suppose that the others have.
        It seems justifiable to conclude, therefore, that except for rare occasional breaches of the rule, we may rely on the observed influence of the mammary function upon the uterus, to secure immunity from conception while lactation lasts; and even in those cases in which this reciprocal action fails, we would suggest that the experience of both cultivated and uncultivated mankind, regarding the reliability of this rule, is so widespread and universal, that possibly some abnormal factor, or undesirable and unessential exciting cause, may be suspected as lying behind its exceptional

        1 All the authorities we have quoted recognise and state this quite plainly.

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failure. We have ourselves witnessed many cases in working-class families, where lactation has thus proved again and again an unfailing safeguard against a too prompt recurrence of pregnancy, without the use of contraceptives, — in fact we know of no exception, and we suggest as possible causes (apart from abnormalities of constitution) for the failure of the rule, one or all of the following adverse circumstances:—
        (1) Excessive, intemperate, or too fiery intercourse during lactation.
        (2) Temporary atonic or inadequate breast function (much more rare than is generally claimed. See opinion of Dr. Janet E. Lane-Claypon). 1
        (3) Frequent but generally concealed dislike of particular women for the function of lactation (from what cause soever), which leads to a strong desire for it to cease, and consequently to a perfunctory attention to it while it lasts. Such an attitude is not uncommonly accompanied by unfounded complaints to the family doctor that the act of suckling produces pain. 2
        But these are only suggestions; for the question why the influence of lactation upon conception fails in exceptional cases does not appear to have been investigated by modern medicine.

        1 Milk and its Hygienic Relations, pp. 147–9.
        2 The reader is reminded here that in the above discussion we have not been concerned in any way with those women who cannot under any circumstances suckle their child. In these abnormal cases (rare according to Janet E. Lane-Claypon) abnormal correctives must, of course, be used. They are not sound, and cannot therefore be left to Nature. In their case contraceptives are indicated for the purpose of spacing births. See pp. 55–6 and 58 (footnote).

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        We have therefore arrived at the following conclusions:— (a) Having examined the average interval that occurs before the birth of the first child in a large number of couples who could hardly be suspected of using contraceptives (for, apart from the years from which the data were derived, it is unusual for contraceptives to be used so soon after marriage), we have seen that, in human beings, fertilisation does not by any means follow regular intercourse as quickly as it does in animals, and, therefore, that a certain margin of delay may reasonably be added to the normal interval between births, quite apart from the other causes which determine this interval in the majority of cases.
        (b) Having examined certain averages relating to the interval between births, either among people who could not be suspected of making use of contraceptives, or from a period of last century when contraceptive practices and expedients were known and accessible only to a very few, we have seen that some cause must operate to make the average interval between births longer than the period of gestation, plus the period allowed for recovery after each confinement, and the variable delay mentioned under (a) — say eleven to fourteen months.
        (c) Having dismissed continence and contraceptives, we have been reduced to the possible explanation that there may be antagonism between the function of the breast and the womb, and we have seen this abundantly confirmed both by the general experience of mankind and the investigations of anthropologists and modern medical men.
        (d) Thus we have inferred that, although the rule is not without exceptions, which are admittedly rare,

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conception does not occur during lactation, and therefore, that births are more likely to be normally spaced and the interval between them sufficiently long to avoid any exhaustion of the mother by too frequent pregnancies where children are fed at the breast.

*        *        *        *        *

        The next question that occurs to us, and one which is quite independent of the above conclusion, and does not affect it, is — can the interval of infertility be deliberately prolonged, beyond the average twenty to twenty-six months, by prolonging lactation?
        What is meant by this?
        An interval of twenty-six months or two and a half years would imply a maximum period of eighteen months of lactation — probably less in the majority of cases, owing to the delay to be reckoned with, which is mentioned under (a). Could lactation be prolonged to, say, twenty-four months, in order to obtain an interval of three years?
        Needless to say that this is frequently done not only among the poor of England, but, as we have seen, among hundreds of savage races. Dr. Wrench has been quoted as saying that it is natural and that the practice is widespread. Not only that, but both among the poor and the savage peoples referred to by Mr. Briffault it is successfully done — that is to say, neither the child nor the mother appears to suffer from it. And we have ourselves known of several cases among the poor in North Kensington, in which a most successful child has been reared after two and a half years and even three years of lactation without injury to the mother. We are, moreover, prepared to introduce any enquirer to these cases if he is interested.

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        Let us, therefore, be quite sure why people are so prone to condemn this practice nowadays, and let us be certain that the demand for freedom among women is not perhaps the primary cause of the mass of expert opinion that could be quoted against it. For there can be no question that if it had been unreliable or deleterious to mother and child, it would long ago have been abandoned, at least by primitive peoples, or else have exterminated them. Of course it presupposes healthy conditions, but almost every normal practice does. And once more it must be pointed out that it is not invariably reliable as a preventive, any more than lactation for the usual term is, and probably for the same reasons.
        Writing on this very point, Dr. Iwan Bloch says that its "anti-conceptional effect would, in the majority of cases, fail to occur." 1 But we should very much like to know his reasons for this blunt denial of its efficacy, and above all the data on which he relies for making it. For it seems to us that in order to make good his claim, Dr. Bloch would have to show the unreliability of a mass of anthropological and other data, all of which tend to prove, not only that lactation is often prolonged successfully in order to increase the interval between births, but that this prolongation also does no damage to child or parent. It is true that, among

        1 Op. cit., p. 701. A more sober and impartial statement on this subject is made by Dr. Kisch (The Sexual Life of Woman, p. 403); "Artificial protraction of the period of lactation is an old and well-known method, practised by many savage people, for the prevention of fertilisation. As a general rule, as long as lactation continues, amenorrhea persists, and sexual intercourse remains unfruitful. But this rule also is not universally valid."

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savages, marital intercourse is frequently suspended altogether during lactation, but this is not invariably the case, and in Europe it occurs but rarely.
        Let us be quite clear, however, concerning the nature of this prolongation of lactation. Neither with the savages among whom it is practised nor with the civilised poor among whom we have witnessed it, does it mean that the child is sustained solely on the breast until it is one and a half or two years old. For if it meant this it would obviously be most harmful and the criticism against it would be entirely justified. But it does not mean this. In practice I have never found it mean more than that the growing infant, instead of being put on a diet consisting partly of cow's milk and partly of solids, at the age of ten months or a year, retains breast milk as that portion in its daily diet which still consists of milk, while for the rest it is given progressively the same increasing amount of solids as the child who leaves the breast at the so-called weaning period. For, as a general rule, as every mother knows, weaning does not mean the complete cessation of a milk diet. It usually means changing the child over from an exclusive milk diet (breast) to a diet consisting partly of cow's milk and partly of solid food. When lactation is wisely prolonged, therefore, it only means that the child goes to the breast for that quota of milk which still constitutes part of its daily food. And in those cases in which I have seen breast-feeding successfully prolonged up to eighteen or twenty-four months, this has always been the method, adopted. Gradually educated to subsist on solid food, the child has still continued to receive breast milk instead of cow's milk for its daily portion of milk, until such time

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as it can subsist entirely without milk, when it ceases to be suckled. 1 It is at this moment, in families where lactation has not been prolonged, that cow's milk ceases to be a regular portion of the child's diet.
        There is a good deal to be said for this practice, and that it can be entirely successful nobody who knows anything about the poor would dream of doubting. The fact that it is also, despite Bloch's rather wild and unscientific denial, a reliable means of contraception, has too often been demonstrated to be so lightly dismissed. Nobody would claim that it is an infallible means of prolonging the interval between births; it is so no more than lactation for nine or ten months is. But it is not improbable that when it fails, its failure is occasioned by causes very similar to those to which reference has already been made in regard to the failure of the usual nine or ten months' lactation.
        Finally, and by way of summing up, perhaps it may interest the reader to hear the opinion expressed in a recent gynæcological treatise on this very question.
        In Dr. Fairbairn's Encyclopædia of Midwifery and the Diseases of Women 2 there occurs the following profoundly interesting passage which, in its freedom from bias, is rare enough in gynæcological literature:—

"The view that at the age of 8 or 9 months breast milk should cease to be given and should be replaced by large quantities of cow's milk is a modern view, and is certainly not a biological view. It is further one to which scarcely any attention is paid by large numbers of women, who neverthe-

        1 This gradually diminishing provision of milk does not seem to do any harm to the mother either among savages or our own poor.
        2 Edition 1921, p. 349.

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less rear their children with evident success. In stating this there is no intention to suggest that breast feeding should be thus prolonged in every instance, but rather to show that the success which so often attends the practice may well allow us to examine it without prejudice. . . . The common accusation that prolonged breast feeding is frequently associated with rickets does not in reality affect the argument. The etiology of rickets is not fully understood nor is its discussion within the scope of this article."

        Thus in considering the practice of prolonging lactation in order to prevent pregnancy, we must understand what this means in our present context. It means no more than substituting breast milk for cow's milk during the period when the child is becoming habituated to solid food. It therefore means providing the child with a progressively diminishing quantity of milk from, say, its tenth or twelfth month to the time when it is one and a half to two years of age. And when it means no more than this, it will not only be found successful, provided the conditions are healthy, but it will also, in the majority of cases, prevent conception, and enable the highest estimate for the optimum interval (three years) to be attained, without any contraceptive practices. When it is understood to mean sustaining a child over ten months old on breast-milk alone, it is of course vicious and harmful, and cannot help proving injurious both to parent and child. It is not, however, a practice which it would be advisable to recommend too widely, as the optimum conditions of health which it presupposes are, to-day, comparatively rare. But there would be less need of it if the population and the burdens of degeneracy were reduced on the lines discussed in Chapter X.



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