112 



THE GROWTH OF THE BRAIN. 



for the length of the head, a relation which is less clear 

 in the curves for breadth, but still suggested by them. 

 Moreover, since the curves for both measurements fail 

 to indicate that these growth changes have ceased even 

 at the age of twenty-one years, further observations 

 would be of value. 



AGE 



579 II 13 15 



YEARS 

 17 19 21 



mm. 



ISO 



140 



- GizrlS 



mm. 

 190 



ISO 



!70 



FIG. 18. Showing the changes in the length and breadth 

 of the head between the ages of five and twenty-one 

 years. A. The curve for length. B. The curve for 

 breadth. (West.) 



The records of brain-weight do not, however, clearly 

 indicate increase beyond this age, but in making any 

 comparison it must be borne in mind that the observa- 

 tions by West were on living children developing under 

 fairly favourable conditions, while those collected by 

 Vierordt were from necropsies on the least favoured 

 classes, and also that all the increase in these dimensions 

 of the head is not to be directly referred back to the 

 encephalon, but due allowance should be made for the. 



