8 Franklin P. Mall. 



persons of only ordinary abilities" (p. 303). What lie says regarding 

 the callosum of Leidy is true, but regarding the rest he is in error. All 

 the rest of the callosa of notable men given by Spitzka are not above 

 the average for brains of the same weight, and the callosa given in his 

 group of ordinary men (which are from electrocuted criminals) are 

 very much below the average (compare Spitzka's Tables A and B with 

 Bean's Chart V and with the data given in my table). In fact 

 many negroes of lighter brain weight have larger callosa than 

 most of Spitzka's eminent men. Cope's callosum as measured by 

 Spitzka is far below the average of brains weighing over 1500 grams. 

 Comparing Spitzka's records with Bean's and mine it would be 

 more correct to state that criminals have callosa much smaller than 

 the average. 



Furthermore, Bean believed that he had shown that the genu is 

 relatively larger and the splenium is relatively smaller in the negro, 

 an assertion which is even more striking than Spitzka's. From this 

 as well as from other data Bean deduced that the frontal lobe is 

 smaller in negro brains than in white. This is in apparent con- 

 tradiction to the results he obtained by comparing the position of 

 the central sulcus, which in 126 hemispheres holds about the same 

 position in the two classes of brains. If anything, it lies more 

 posterior in the female negro (Table IVa, p. 381) which would 

 indicate that her frontal lobe is relatively the largest of all. 



All of Bean's measurements are made from a brain axis which 

 passes in the sagittal plane between the two hemispheres immediately 

 above the anterior commissure and just below the splenium. As a 

 rule this line (the axis) passes parallel with the longest axis of the 

 corpus callosum and just below it. From this line he erected two 

 perpendiculars, one just in front of the genu and one just behind 

 the splenium. The distance between the two perpendiculars was 

 then divided into ten parts, the first three, including the genu, he 

 calls the genu, the second three the body, the next two the isthmus 

 and the last two, including the large rounded splenium, the splenium. 

 He then compared the area of the genu with that of the splenium, 

 using the former as ordinates and the latter as abscissae in the con- 

 struction of his Chart VII. It was found by this treatment that 



