50 THE GROWTH OF THE BRAIN. 



the general method. It is also perfectly clear that the 

 number of observations on which the first part of the 

 curve is based, is too small ; and that the course of 

 the curve for the first five years is not nearly so well 

 determined as for the next twenty. So, too, the different 

 classes in the community are not proportionately repre- 

 sented at the different ages, and another slight error is 

 thus introduced, but on the principal points these data 

 are sufficiently accurate. 



The differences in individual growth are dependent 

 on a variety of other conditions. It has often been 

 observed that illness retards the growth of children, and 

 that on recovery from illness there is a tendency to recover 

 the weight and stature which should normally have 

 been attained ; hence just after illness the child may 

 grow with unusual rapidity. These facts are admirably 

 illustrated by Fig. 11, taken from K. Vierordt, where in 

 one case Y and Y', pneumonia causes the increase in 

 stature to cease and weight to be lost, and in Z, a slight 

 bronchitis prevents for a short time any gain in weight. 1 



The younger the child the more readily the recupera- 

 tion is accomplished. Although external conditions 

 have but a slight influence on the general course of the 

 growth curve, yet the specially favoured classes in 

 England and the United States are plainly above the 

 average of the community in both weight and stature. 

 At the same time it is hardly proper to assume that 



1 The measurements in this figure are in grammes and centi- 

 meters. For those not familiar with the metric system, the 

 following equivalents are given : 



' = 1 Inch 



3 Centimeters 



One inch is approximately 2 '5 cm. 

 One pound avoirdupois, 453'59 grms. 

 One ounce 28-35 



