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THE FUTURE OF OUR POPULATION

THE LANCET

LONDON: : SAT Z7RDA F, APRIL 17, 1937 7

THE observant man can hardly be blamed ifhe has a feeling of bewilderment, tempered perhapsby scepticism, when he considers the figures relatingto population. For years economists and other

experts have made the spectre of over-populationdance before his eyes. He has been told that

poverty and misery must be reduced by volitionalcontrol of the size of the family-that the

" planned "

family is the ideal at which we mustaim. There seems, moreover, ample justificationfor the argument. He knows that the populationof our country has shown a phenomenal increase,that it has multiplied nearly fivefold in rathermore than a century, and that it now dependslargely upon distant sources for its food-supplies.Looking, even casually, around him he seems tosee additional evidence on every side ; there is acontinual encroachment of the town upon the

country, building activity in every direction, town-planning schemes in operation or visualised, trafficcongestion on road and rail affecting his everydaylife, depressing figures of unemployment, unsatis-factory diets amongst the larger families in thepoorer strata of society, and an annual excess ofbirths over deaths so that the numbers in the

country continue to increase.And yet the expert now tells him that we are

seriously threatened with depopulation. In the

daily press, and in books and pamphlets, he iswarned gravely that our population must shortlyfollow a downward path, that unless people soonbegin to have more children we shall be threatenedwith extinction, that a Royal Commission oughtat once to be appointed to " discover the factsand to formulate a population policy."’ 1 Whatis he to believe ? What is the explanationof the seeming paradox ? An excellent attemptto answer these questions in simple terms hasnow been made by the Population InvestigationCommittee. This body, formed last autumnunder the chairmanship of Prof. A. M. CARR-SAUNDERS, includes representatives of the BritishCollege of Obstetricians and Gynaecologists, theMedical Research Council, the Royal EconomicSociety, the Society of Medical Officers of Health,the British Population Society, the EugenicsSociety, and a number of medical and economicauthorities. It was formed to examine the factorsinfluencing contemporary trends of population inEngland and Wales with special reference to thefall of the birth-rate. Its first task has been toconsider the recent history of our population, todetermine how its prodigious growth has takenplace, what effect the declining fertility-rate is

1 Times, April 5th, 1937.

likely to have upon its future size and constitution,and what have been the basic causes of that fallin fertility. The results of these inquiries are setout in a pamphlet prepared for the committeeby Dr. C. P. BLACKER and Mr. D. V. GLASS.2When the population began to increase towardsthe end of the eighteenth century it is possiblethat there was some rise in fertility, but theevidence is .scanty. Throughout the nineteenthcentury the rise was certainly not due to an

increasing birth-rate but to a falling death-rate.Between 1838 and 1913 the births annuallyexceeded the deaths by about 300,000 ; in thedecade 1914-23 the excess was only 220,000 ayear ; in 1934 it had fallen to 121,000. Thoughthere is likely to be an excess in 1937 it will bestill smaller, and in another five years, or less,that excess will have vanished. One result ofthis falling birth-rate is the raising of the averageage of the population. In time this must lead toan increase in the crude death-rate-althoughwith further advances in medical science and publichealth the death-rates at ages may continue todecline. A population that contains a largeproportion of old people must have a relativelyhigh death-rate and it is on this rate, in con-

junction with the fertility-rate, that the growth ofthe population must depend. With an ageingpopulation we clearly cannot depend upon favour-able changes in the death-rate to maintain ournumbers. To take a simple example, Dr. G. F.MCCLEARY has shown 3 that the effect on popula-tion growth of an entire elimination of infant

mortality would be completely neutralised by areduction in the birth-rate of less than 1 per 1000.It is mainly on fertility that the future populationmust depend, and although at present the birth-rate remains higher than the temporarily loweredcrude death-rate, it is now well below the replace-ment-rate. It is, in fact, to this rate that wemust look, and the figures of the 1931 census ofEngland and Wales show that persons aged 20-35were more numerous than the young persons inthe age-groups 0-15 : in other words, there werein 1931 not enough young people to replace themen and women twenty years older than them-selves. With the aid of a relatively new statisticaltechnique the level of this replacement-rate can bemeasured-by an index known as the net reproduc-tion-rate. Briefly this expresses the number ofwomen who in the next generation will replace thewomen of reproductive age in this generation. Inthe words of BLACKER and GLASS :

" if the women of reproductive age in this generation,who are mothers of children are having sufficient girlchildren to replace themselves as well as those womenof their age who are childless, the net reproduction-rateis 1 or unity and the population is maintaining itself.If, allowing for deaths, they are not having enoughgirl children to do this, the net reproduction-rate fallsbelow unity and the population is not replacing itself ;if they are having more girl babies than is necessary

2 The Future of Our Population. By C. P. Blacker and D. V.Glass. Issued by the Population Investigation Committee,69, Eccleston-square, S.W.1. Pp. 31. 6d.

3 The Menace of British Depopulation. By G. F. McCleary,M.D. London: George Allen and Unwin. 1937. Pp. 144.4s. 6d.

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for this purpose, the net reproduction-rate is aboveunity and the population will increase."

Dr. ENID CHARLES 4 has calculated that in 1933the figure for England and Wales was only 0’734,or according to the fertility- and mortality-ratesof that year 1000 women of reproductive agewere producing only 734 girl children who wouldgrow up to replace them in the next generation.The figure is below unity in most of the countriesof western Europe and, as MoCLEARY emphasises,amongst the British-born in the Dominions. Itis easy, though laborious, to calculate the down-ward path along which this present position mustlead us, and an example of the calculation, byMr. C. A. GOULD, is given on p. 944. Naturallythe further ahead we endeavour to prophesy themore we may deviate from the truth. But evenif fertility ceases to decline below its present levelwe are faced with a declining population in thenear future, and with a population that somebelieve will deteriorate in quality as well as

quantity, through the effects of differential fertility.As BLACKER and GLASS admit, many good

arguments can be urged for preferring a stationaryor a slowly growing population to a rapidlyexpanding one ; but a declining population is

quite another matter. Only an increased fertilitycan avert it. Is that a likely event ? Are there

any means of encouraging it ? Unless we knowthe reasons for the falling birth-rate we clearlycan take no steps to arrest its decline. In thesecond section of their pamphlet BLACKER and GLASSdevote themselves to this subject. Sterility theythink is not increasing and they lay more stresson social and economic reasons-the difficulty ofparents supporting more than a small number ofchildren, of finding them suitable employment asthey reach maturity, of giving them and them-selves the social advantages, comforts, andstandards of life that they desire. Under psycho-logical reasons they refer to the parental instinctthat is satisfied by one or two children-" whenparenthood is being increasingly planned, the

strength of the desire for children as measured

by the number of children by which it can be

adequately satisfied, comes into an entirely newprominence as a biological factor to which isattached the clearest survival value." The uncer-tain political and social condition of the worldmust also play its part. Fertility cannot beraised, they conclude, unless there is a change ofattitude of the kind they call " psychological "about the family, unless people can somehow beinspired to want children. MCCLEARY is much ofthe same mind. Though he is satisfied thateconomic factors are at work, he thinks that thereally important causes of depopulation lie deeperin the conditions of modern life. " If babies arenot to be had for love they are not likely to behad for money." Certainly the efforts by thelatter means taken in Germany and Italy havebeen attended by no striking success,5 though theeconomic incentives offered may well have been

4 The Twilight of Parenthood. London. 1934.5 The Struggle for Population. By D. V. Glass. Oxford.

1936. See Lancet, 1936, 2, 441.

too small. But if effective action is to be takenwe must know more of the possible factors thatare thought to influence people in restricting theirfamilies. This problem the Population Investiga-tion Committee hopes to investigate, and an

appeal is made for funds to enable it to do so.There are two lines it wishes to follow-namely,statistical analysis and direct inquiry. Under thefirst, calculation may be made of the extent towhich people living in different regions, urbanand rural, and working in different industries andoccupations, are replacing themselves. Underthe latter, by questionnaire, further light may bethrown on differential fertility, on medical causesof infertility, on the degree of success attendingcontraception, on the effects of uncertainty ofemployment, on the " psychological " factorsinvolved. Perhaps, as some have argued, there is alaw of population growth or there are, as BROWNLEBbelieved, changes in germinal vitality that wecannot influence. Perhaps, as others believe," the innumerable distractions of modern life arefar more tempting to the average man and womanthan is the bringing up of children," the only remedyfor which is the " reawakening of the race as a wholeto its responsibilities as a civilising factor." 6 The

problem is exceedingly complex, but of vitalnational importance if " western civilisation isnot to go the way of Greece and Rome to decayand death." That fear some may think undulyalarmist, but the pamphlet under review showsclearly the experts’ reasons for disquiet. It givesno one an excuse for remaining ignorant of thesituation.

NEW METHODS OF IMMUNISATIONAGAINST DIPHTHERIA

To protect a particular child against diphtheriais comparatively easy : there is a wide choice of

immunising agents and methods which are all

reasonably satisfactory for the purpose. To

protect a community is far less simple, since themethod adopted must be uniform, must give ascomplete and lasting protection as possible,must not produce serious reactions, and must becheap and manageable. The dilemma is wellknown and no way of circumventing it has beenfound.’ The difficulty is that, on the one hand,a single injection either fails to give immunityin a satisfactory proportion of cases or causes toosevere reactions, while on the other hand, mothersdo not like to bring their children for a series ofinjections, particularly if these have to be repeatedat intervals in order to keep the antitoxin at asuitable level.A possible way out was demonstrated by Prof.

CLAUS JENSEN, director of the department ofbiological standards at the State Serum Instituteof Copenhagen, in a paper given to the epidemio-logical section of the Royal Society of Medicineon April 9th. The method he adopts, which is

supported by many years’ work and much experi-ment, is a single subcutaneous injection of Schmidt’s

6 Daily Telegraph, April 6th, 1937.