94 



THE RATE OF GROWTH 



[CH. 



the stature at birth by about 1 per cent, exceeds it at the age of 

 twenty by about 4 per cent. After the age of twenty, Quetelet's 

 data are few and irregular, but it is clear that the span goes on 

 for a long while increasing in proportion to the stature. How 

 far the phenomenon is due to actual growth of the arms and 

 how far to the increasing breadth of the chest is not yet ■ 

 ascertained. 



Fig. 19. Ratio of stature in Man, to span of outstretched arms. 

 (From Quetelet's data.) 



The differences of rate of growth in different parts of the body 

 are very simply brought out by the following table, which shews 

 the relative growth of certain parts and organs of a young trout, 

 at intervals of a few days during the period of most rapid develop- 

 ment. It would not be difficult, from a picture of the little 

 trout at any one of these stages, to draw its approximate form 

 at any other, by the help of the numerical data here set 

 forth*. 



* Cf. Jenkinson, Growth, Variability and Correlation in Young Trout, 

 Biometrika, viii. pp. 444-455, 1912. 



