18 Franklin P. Mall. 



brain are in all probability due to similar racial peculiarities of 

 the skull. The same statement is also made by Hrdlicka and has been 

 fully tested by Bean. However, such differences are but slight, 

 for a variation in the shape of the skull influences only the main 

 outlines of the brain and not its gyri. The flattening over the anterior 

 association area, as first observed by Hrdlicka, was fully confirmed 

 by Bean and can be seen in most full-blood negro brains, certainly 

 in more than one-half. One precaution must always be taken in 

 these cases and that is to compare whites and negroes of the same 

 type of form of the skull. The majority of negroes are dolichocephalic 

 and these should be compared only with dolichocephalic whites. 



In order to make a preliminary test of this question I attempted 

 to assort a collection of negro and white brains, calling those with 

 the peculiar narrowing and flattening of the upper surface of the 

 frontal lobe, negro, and those in which it was more convex, white 

 brains. The brains tested were a mixed lot which happened to be 

 on one shelf in the brain room. After they had been assorted accord- 

 ing to the character above mentioned I found that there were 60 

 negro and 30 white brains and that their assortment was correct 

 in exactly 75 per cent of the cases. Had all of the brains been 

 dolichocephalic I think the test would have fallen out better, and Dr. 

 Hrdlicka informs me that this is also his opinion. 



I then mixed the brains again, added to their number, and as- 

 sorted them a second time according to the richness of the gyri and 

 sulci, using as a standard the two illustrations given on Plate 54 in 

 Retzius' Mensclienliirn. In case the configuration was complex, of 

 the Gauss type, it w^as called stenogyrencephalic, and in case it was 

 simple, of foetal type, it was called eurygyrencephalic. Doubtful 

 specimens, and there were many of them, were at first set aside and 

 in case it was impossible to render a decision regarding them by 

 a second effort they were excluded altogether. 



The results of this test, based upon brains of unknown origin at 

 the time it was made, are given on the opposite page. . 

 ' The percentage of eurygyrencephaly and stenogyrencephaly is 

 therefore about the same in both races. 



In order to make a further comparison the brains pictured in 



