98 THE RATE OF GROWTH [ch. 



between them are significant enough. There is some tendency for 

 growth in weight to fall off or fluctuate at four or five years old, 

 before the small boy goes to school ; but there is, or should be, httle 

 retardation of weight when growth in height slows down before 

 he enters on his teens*. The healthy lad puts on weight again 

 more and more rapidly, for some httle while after gjowth in stature 

 has slowed down; and normal increase of weight goes on, more 

 slowly, while the man is "fiUing out," long after growth in stature 

 has come to an end. But somewhere about thirty he begins losing 

 weight a httle ; and such subsequent slow changes as men commonly 

 undergo we need not stop to deal with. 



The differences in stature and build between one race and another 

 are in hke manner a question of growth-rate in the main. Let us 

 take a single instance, and compare the annual increments of 

 growth in Chinese and Enghsh boys. The curves are much the 

 same in form, but differ in amplitude and phase. The Enghsh boy 

 is growing faster all the while; but the minimal rate and the 

 maximal rate come later by a year or more than in the Chinese 

 curve t (Fig. 6). 



Quetelet was not the first to study man's growth and stature, 

 nor was he the first student of social statistics and "demography." 

 The foundations of modern vital statistics had been laid by Graunt 

 and Petty in the seventeenth century J; the economists developed 

 the subject during the eighteenth §, and parts of it were studied 



♦ That the annual increments of weight in boys are nearly constant, and the 

 curve of growth nearly a straight line at this age, especially from about 8 to 11, 

 has been repeatedly noticed. Cf. Elderton, Glasgow School-children, Biometrika, 

 X, p. 283, 1914-15; Fessard and others, Croissance des Ecoliers Pariaiens, 1934, 

 p. 13. But careful measurements of American children, by Katherine Simmons 

 and T. Wingate Todd, shew steadily increasing increments from four years old 

 tiU puberty {Growth, n, pp. 93-133, 1938). 



t For copious bibliography, see J. Needham, op. cit., also Gaston Backmah, Das 

 Wachstum der Korperlange des Menschen, K. Sv.Vetensk. Akad. Hdlgr. (3), xiv, 1934. 



X Cf. John Graunt's Natural and Political Observations. . .upon the Bills of 

 Mortality, London, 1662; The Economic Writings of Sir William Petty, ed. by 

 C. H. Hull, 2 vols,, Cambridge, Mass., 1927. Concerning Graimt and Petty — two 

 of the original Fellows of the Royal Society — see {int. al.) H. Westergaard, History 

 of Statistics, 1932, and L. Hogben (and others). Political Arithmetic, 1938. 



§ Besides the many works of the economists, cf. J. G. Roederer, Sermo de 

 pondere et longitudine recens-natorum. Comment. Soe. Beg. Sci. Oottingae, m, 

 1753; J. F. G. Dietz, De temporum in graviditate et partu aestimatione, Diss., 

 Gottingen, 1757. 



