Ill] OF GROWTH IN MAN AND WOMAN 101 



growth in infancy ; (6) the steady growth in early boyhood ; (c) the 

 period of retardation which precedes, and (d) the rapid growth which 

 accompanies, puberty. 



Buifon, with his usual wisdom, adds some remarks of his own, 

 which include two notable discoveries. He had observed that a 

 man's stature is measurably diminished by fatigue, and the loss soon 

 made up for in repose; long afterwards Quetelet said, to the same 

 effect, "le lit est favorable a la croissance, et le matin un homme est 

 un peu plus grand que le soir." Buff on asked whether growth 

 varied with the seasons, and Montbeillard's data gave him his reply. 

 Growth was quicker from April to October than during the rest of 

 the year: shewing that "la chaleur, qui agit generalement sur le 

 developpement de tous les etres organisees, influe considerablement 

 sur I'accroissement du corps humain." Between five years old and 

 ten, the child grew seven inches during the five summers, but during 

 the five winters only four; there was a Hke difference again, though 

 not so great, while the boy was growing quickly in his teens; but 

 there were no seasonal differences at all from birth to five years old, 

 when the child was doubtless sheltered from both heat and cold*. 



On rate of growth in man and ivoman 



That growth follows a different course in boyhood and in girlhood 

 is a matter of common knowledge; but differences in the curves "of 

 growth are not very apparent on the scale of our diagrams. They 

 are better seen in the annual increments, or first differences; and 

 we may further simplify the comparison by representing the girl's 

 weight or stature as a percentage of the boy's. 



Taking weight to begin with (Fig. 9), the girl's growth-rate is 

 steady in childhood, from two or three to six or seven years old, 



* Growth-rates based on the continuqus study of a single individual are rare; 

 we depend mostly on average measurements of many individuals grouped according 

 to their average age. That this is a sound method we take for granted, but we may 

 lose by it as well as gain. (See above, p. 92.) The chief epochs of growth, the chief 

 singularities of the curve, will come out much the same in the individual and in the 

 average curve. But if the individual curves be skew, averaging them will tend to 

 smooth the skewnesa away; and, more curiously, if they be all more or less diverse, 

 though all symmetrical, a certain skewness will tend to develop in the composite or 

 average curve. Cf. Margaret Merrill, The relationship of individual to average 

 growth, Human Biology, iii. pp. 37-70, 1931. 



