190 WILDER— BRAIN OF HALF AVERAGE WEIGHT. [April 22, 



or white substance rather than in the cortex or gray matter; upon 

 these points and upon the size of the callosum I hope Dr. Spitzka 

 may be wilhng to comment even at such short notice. 



Fissural Peculiarities. — Of these there are several, and some are 

 indicated upon the charts. Their detailed discussion would be out 

 of place in a comprehensive society like this until such time as the 

 normal human fissural pattern is familiar to pupils in or below the 

 high school. 



This brain is not ape-like. Even were it still smaller it is 

 distinctly human. The mesal cleft or " valley " of the cerebellum 

 is deeper than in any ape. The calcarine and occipital fissures are 

 deeply continuous while, with rare exceptions, they fail to unite in 

 apes. Even the insula, deficient as it is, does not resemble that of 

 apes, and the " speech-center" is of the human type. 



Brain-zveight and Intelligence. — Upon the present occasion at- 

 tention is particularly directed to this exemplification of the possi- 

 bility that ordinary human intelligence may apparently coexist with 

 a brain of only one-half the ordinary size, exceeding that of cer- 

 tain apes by only 180 grams (about six ounces), and not quite 

 double the size of the brain of a congenital idiot. 



