10 SEPTEMBER 1927, Page 8

The World Population Conference

[We need make no apology to our readers for deferring the publication of Mr. Eldon Moore's second article on An Unpopular' Aspect of National Health, in view of the importance of this contribution, which we have just received from him from Geneva. —ED. Spectator.] THE World Population Conference, which ended last week (September 3rd) at Geneva, Was undoubtedly a success. Subjects never before discussed outside a very limited circle were at least given' a 'public airing. Public opinion was for the first time concentrated,- by the assemblage of two to three hundred scientists - from all over the world, upon a factor which always has underlain the social and economic problems in the past, and which now threatens to be the gravest concern, national and international, of the governments of the near future. Scientists who knew little of each other and each other's work were brought into close personal contact, whilst their various theories were subjected to mutual criticism. Above all, as a direct result of the Conference, a permanent international organization is to be set up "to consider in a purely scientific spirit the problems of population." As Prof. H. B. Fairchild (U.S.A.) said, the desire for a large population is some- times prompted by "sheer megalomania, an unreflective desire for bigness for its own sake," and at others by "militaristic necessity or advantage." Both emotions seemed to actuate the Italian speakers, who seemed to echo Signor Mussolini's demand for ten million babies in thirty years. How the growing population was to be fed, or where it was to go when it outgrew the national boundaries, were questions not considered. Indeed, the Latin members generally of the Conference united with the one Japanese speaker in an attack upon immi- gration laws. They introduced a highly debatable ethic, declaring that countries with open spaces and colonizable lands were not justified in closing their gates to all or some corners. Selective immigration was particularly deplored by Dr. Inui of• Japan.

It was, therefore, perhaps just as well that Australian speakers were absent. For, whilst rumblings had already been heard at other sessions, that on migration was peri: lously like an international dog fight. Dr. C. B: Davenport' and Prof. E. M. East put the American case for restricted immigration with commendable - restraint, laying stress not only on the quantitative, but also on the qualitative, or eugenic, aspect. The latter may have been a little vigorous in expressing the view that emigrants from a country are usually its outcasts and therefore biologically undesired by the country of immigration (this, by the way, is true of almost all emigrants except those from Great Britain, where the Poor Law and " dole " keep at home the defective and ineffective, whilst lack of opportunity and adequate incentive drive abroad the most able and vigorous). But Dr. Davenport, for the sake of international courtesy, withheld his trump card—the extraordinarily high incidence of inherent defects and a-social qualities in the American- born children of immigrants. This interesting pheno- menon, which can only be explained by the Mendelian theory, suggests that immigrants are usually the best individuals of poor stock, carrying latent, or " recessive," factors in their blood. On the mating of like with like, these factors become patent in• the children.

Returning, however, to the quantitative aspect, it was most remarkable that only Prof. East among all the speakers seemed to have learned the lesson con- tained in Prof. Raymond- Pearl's paper, "The Biology of Population Growth." , After exhaustive experiments, with yeast-cells, bacteria, and flies, Dr. Pearl discovered that all these types of organisms had the same rate of population growth. The population at first grows slowly, but gains inipetns as it grows, passing• gradually into a stage of rapid growth which finally -reaches a maximum of rapidity. After this the population increases ever more and more slowly until finally there is no perceptible growth at all. The process is described graphically as a "logistic" curve. Dr. Pearl claimed that the same growth curve was exhibited by the native population of Algeria, by that of many civilized countries, and even of the world. His theory was that the popula- tion's own density was the automatic, self-regulating governor of growth. Whilst there is elbow room, so to speak, the birth-rate is high and the death-rate low. When elbow-room gets scarce, then the latter rises and the former falls.

After the criticisms of, among others, Dr. R. A. Fisher Mr. J. B. S. Haldane, and Prof. Julian Huxley, it would be going too far to assume the logistic curve to govern the rate of growth of all organisms. In particular, the census records of human populations cover too short a period of time to furnish substantial confirmation. Also, as Prof. Pearl himself says, the logistic curve only obtains when the food supply is fully adequate. Other- wise the latter is the regulating factor : and he admitted that, in his opinion, it was chiefly operative in Europe to-day. -- The rate of growth of the United States in following the logistie curve since 1790 is strong confirmations of Dr. Pearl's hypothesis. It is also a most significant comment upon the theory that migration is a cure for over-population. The American census records show no trace of the vast amount of immigration into that country during the period. The rate of growth, in short, -has been along the logistic curve, fewer births and more deaths having compensated for the influx from outside. The converse holds equally firmly of the country from which a flow proceeds. In Prof. East's words, "If emigration takes place from a country in which there is population pressure to a so-called under- populated country, there is an immediate increase in the birth-rate of the former country which restores the equilibrium."

This is a fact which should be burned in upon the minds of all those individuals and countries who clamour that "the vacant spaces of the world," no matter to whom they belong, offer the solution to the over-populated corners. How many people realize that China is not over-populated ? As Prof. _Percy Roxby (Liverpool University) pointed out, most of that country is almost deserted, the population having flowed to the most fertile parts. These—like the district at the mouth of the Y-angtse with 6,000 persons to the square mile— are grossly over-populated by a people with a low, standard of living and no conscious control over their natural increase. Such a people, were other races to give them the necessary facilities, would over-populate the world. Pressure of population, either upon food- supply or elbow-room, or both, existed in China, India, and other parts of the world long centuries before Euro- peans, in search of a higher standard of living, opened up the fertile places of the world.

If it has done nothing else, the Conference has at least taught two lessons : (1) that Malthus's teaching remains in essence unshaken ; (2) that each country must find its own solution to the population problem. There can be no shifting of the burden by migration.

ELDON MOORE. Salle Centrale, Geneva.