248 



DISCOVERY 



Reviews of Books 



THE POPLLATIOX PROBLEM. 



The Population Problem: A Study in Human Evolution. 

 By A. M. Carr-Saunders. (The Clarendon Press. 

 Oxford, 2IS.). 



Mr. Carr-Saundcrs' j.tudy of the population problem is 

 planned on comprehensive lines. .\s his sub-title indi- 

 cates, it is not a contribution to the discussion of any one 

 aspect of the problem ; it deals with the whole, or, at 

 anv rate, with the main features, from an historical and 

 •evolutionarv point of view. The chief elements in the 

 problem are traced back to their origin in the biological, 

 anthropological and economic factors which determine 

 the wav in which anv collection of individuals is 

 organised as a human society. In so far as it does this, 

 it advances discussion bv a clear-cut statement of the 

 essential elements of the problem ; but its appeal is 

 directed not so much to the specialist as to those who 

 have a general interest in the question. For such readers 

 Mr. Carr-Saunders' careful and lucid summary of the 

 evidence afforded bv the latest researches in connection 

 with reproduction, heredity .and \ariation, ;md their bear- 

 ing upon the question of the- numbers and the character, 

 both physical and ment.il, of anv given population 

 will be of great value. He is to be congratulated 

 upon the .ability with which he has so handled his 

 material — material, be it said, of a highlv technical 

 character — as to render it intelligible to those who have 

 no intimate acquaintance with the data of the sciences 

 from which he has drawn his arguments. It must be 

 accounted as a merit that the book is written throughout 

 with regard to the ;uithropological point of view. It 

 must also be adinitted, however, that the author's stvle 

 does not make for easy reading, and is even at times t 

 little irritating. 



The discussion of the population problem nia\ be said 

 to begin with the publication by Malthus in 1798 of his 

 Essay on Population. His vie'.vs had to some extent been 

 anticipated ; but the subject had received little more than 

 superficial or partial treatment bv classical, mcdiieval and 

 earlier modern writers. In the main, interest had been 

 directed to the question of numbers. The desire for 

 national aggrandisement had focused attention on the 

 desirability of a large population. Mnlthus expounded the 

 relation of population and food supplv. He maintained 

 that, while population increased in geometric ratio, the 

 food supply increased in arithmetical ratio onlv ; but that 

 undue increase of popul.ttion was checked bv vice, disease 

 and misery. Although the accuracy of his data was 

 impugned, his views had a profound effect on the thought 

 of the nineteenth centurv, notablv in their inlTuence on 

 Darwin and Wallace. 



Mr. Carr-Saunders bases his examination of the problem 

 on the relation of fecundity (potential production of off- 

 spring) and fertility (rearing of offspring). In Nature, 



he points out there tends to be a more or less constant 

 balance. Notwithstanding the large number of offspring 

 which mav be produced, especiallv among the lower 

 organisms, a varietv of checks operates to secure that the 

 number of adults remains fairly constant. These condi- 

 tions once applied equally to the ancestors of man. 

 Owing, however, to the evolution of reason, the 

 problem now assumes an entirely different form. There 

 appears in the case of man to have been an increase of 

 both fecunditv and fertility. The author is of the opinion 

 th.-it human fecunditv is usually underrated, and in this 

 connection it is of interest to cite some of his figures. A 

 population of a million, half males and half females, each 

 couple producing two children before the age of twenty, 

 and themselves then dying, would, he estimates, produce 

 ,1 constant population of one million ; but with ;in 

 average of two-and-a-half children the population would 

 increase to 3,050,000 in one hundred years, while ;in 

 average of five children would produce 97,650,000 in the 

 same period. 



.\s it is obvious that the human race has not increased 

 and does not increase at anything like this rate, Mr. 

 Carr-Saunders' aim has been to show what are the causes 

 at work to keep this rate of increase in check. He finds 

 ih.it there appears to be an optimum' number in any 

 given society to which population tends to approximate. 

 The checks operative among species in a state of natun.', 

 that is the dangers to which offspring are exposed, 

 decrease, but their place is taken by others. Numbers 

 mav be kept down by natural selection, but there tends 

 to be some partly conscious adjustment on the part of 

 individuals. In a very able review of the anthropological 

 evidence afforded by primitive peoples, he shows that a 

 varietv of factors tend to keep the population son'.e- 

 where near the optimum level. .Among these are inter- 

 course before puberty, contraceptive methods, abortion, 

 infanticide and analogous practices, as well as prolonged 

 lactation, lack of care of children, war, disease and 

 migration. No one of these appears to be peculiar to 

 anv one grade of culture; they appear whether the com- 

 munitv be engaged in hunting and fishing, pastoral pur- 

 suits, or in agriculture. The explanation of this fact 

 probably is that communities confining themselves exclu- 

 sively to one mode of existence are the exception, whereas 

 in the evidence adduced by the author, the main occupa- 

 tion is made the basis of classification and treated as if 

 it were the sole occupation. Indeed, he himself points 

 out hoW' the prevalence of the different varieties of checks 

 varies according to conditions. Among a nomadic people, 

 for instance, one of the factors in determining the number 

 of a young family will be availability of means of trans- 

 port for children. This would probably operate in the 

 direction of one set of checks, while a mode of existence, 

 partially nom.idic, p.irtiallv agricidtural, such as is found 



' Optimum number in this connexion means that number 

 at which in any given society there is such a balance between 

 population and means of subsistence as will secure the most 

 favourable conditions for the individual and the community 

 as a whole, havins; due regard to the .stage of development in 

 civiUsation of that society. 



