Chapter XX\' 

 THE BRAIN OF MODERN MAN 

 \\ EIGHT AND Indices of the Human Brain 



"^HE weight of the human brain in the full-grown adult is between 

 1 100 and 1500 gm. In the large proportion of cases the male brain 

 II weighs between 1304 and 1502 gm., the female brain, 1 134 and 1332 

 gm. In man the brain seems to show some fluctuation in weight dependent 

 upon the age of the individual. Its greatest weight according to the time of life 

 is found in the middle decades, from thirty to fifty years. Before this time the 

 weight gradually increases until it reaches its middle-age ma.ximum and 

 thereafter decreases, losing progressively as old age advances. Statistics indi- 

 cate that the brain weight of distinguished and talented individual members 

 of the race is somewhat in excess of the average adult brain. Thus, in one 

 hundred distinguished men, the average weight of the brain was 1469.65 gm., 

 about 100 gms. above the average weight of European brains. The usual 

 senile decrease in weight is apparently delayed about ten years in those 

 considered distinguished. The brain weight in different races of man shows 

 some slight differences. Thus, the average Chinese brain weighs 1330 gm., 

 that of the Sandwich Islander about 1300 gm., the brain of the Malay and 

 the American Indian, 1265 gm., the brain of the African Negro, 1245 gm., 

 the brain of the native Australian, 1 185 gm., the brain of the Hindu 1 190 

 gm. The weight of the Latin brain is somewhat less than that of the Teutonic 

 and Slavonic races. 



The following tabulation is based on estimates of the volume of the 

 cranial cavity in the prehistoric races of man: 



Trinil race ( Pithecanthropus erectus) 940 c.c. 



Piltdown race ( Eoanthropus) i ^40 c.c. 



