THE CONDITION OF OLD AGE 17 



cord. In order to study the weight of the brain, it is 

 necessary to compare people of the same size, for the 

 size and weight of the brain depend somewhat upon 

 the size of the individual. Now it has been discov- 

 ered by careful examination of persons of similar size 

 that the brain begins relatively early to diminish its 

 weight. Thus in persons of a height of 175 centi- 

 metres, and over, of the male sex, it is found that in 

 the period from twenty to forty years the brain 

 weight is 1409 grams. But from forty-one to seventy 

 years it has sunk to 1363, and in persons of from 

 seventy-one to ninety it has shrunk to 1330. Women 

 of equal size are not usual, and a more average 

 height for women is 165 centimetres; a woman of 

 such a height is likely to have among the white 

 races, be it understood at twenty to forty years a 

 brain of 1265 grams, at forty to seventy years of 1200 

 and at seventy-one to ninety years of only 1 166 grams. 1 

 I give these figures because they show that there 

 is no guessing, but a definite, positive knowledge, 

 proving that soon after the maturity of life in the 

 individual is reached, the shrinkage of the brain 



1 Ernst Handmann has recently published statistics on the growth of brain, 

 based on measurements at the Leipzig Pathological Institute. See Archiv f. 

 Anat. u. Entwickelungsges,, 1906, p. i. The following summarises his 

 resuks : 



Brain Weight in Grams 

 Age Male Female 



4- 6 1215 1194 



7-14 1376 1229 



15-49 1372 1249 



50-84(89) 1332 1196 



