SOCIETY OF THE UNIVERSITY OP ABERDEEN. 



185 



Middlesex Hospital, that there is an annual decrease in the average 

 weight of the brain in a " General Hospital Population " of rather 

 more than 2 grammes (<S -21974 grm. '5245, f - 27245 grm. 

 4271). 



It also appears probable that the " prime " in brain-weight is 

 reached before the " prime " of the body as a whole, at the age of 

 twenty, or even earlier. 1 



The questions which these facts suggest are : Is this decrease in 

 weight and presumably size of the brain accompanied by any diminu- 

 tion in the size of the head or skull ? or is it entirely compensated for 

 by an increase in the amount of cerebro-spinal fluid in the subarach- 

 noid space, or in the ventricles of the brain ? 



Now Venn, who measured the heads of the undergraduates at 

 Cambridge throughout their entire student period, showed that the 

 length, breadth and height of the head increased during this time, and 

 my own measurement of students at the Middlesex Hospital are in 

 entire agreement with his results, the highest averages occurring 

 between the ages of twenty-five and thirty. See Table I. 



TABLE I. 



1 Biometrika, vol. iv., p. 154. 

 24 



