SOME RESULTS OF A STUDY OF VARIATION AND 

 CORRELATION IN BRAIN-WEIGHT. 



By Raymond Pearl. 



The purpose of this paper is to give a brief account of cer- 

 tain of the more general results of a quantitative study of the 

 variation in the weight of the adult human brain, and of the 

 correlation which exists between this and other physical char- 

 acters. The investigation was undertaken with the idea that 

 by an application of biometric methods to these problems it 

 would be possible to reach somewhat more certain conclusions 

 in regard to them than had previously been attained. As the 

 work progressed its originally planned scope was considerably 

 extended. The complete account of the results has appeared in 

 Biovietrika, Volume 4, No. i. It has seemed advisable to pub- 

 lish a brief summary of some of the more important results and 

 conclusions here. On account of lack of space it will be neces- 

 sary in this paper to state many of the points in a somewhat 

 categorical form without adequate discussion of the evidence 

 on which they are based. A full presentation of the evidence 

 must be sought in the complete paper. 



I. Material. As material for this study the following 

 well known series of brain-weighings were used: (i) Mar- 

 chand's(:02) Hessian series, including 475 male and 281 female 

 complete records for persons between the ages of i 5 and 80 ; 



(2) Bischoff's ('80) Bavarian series, including complete records 

 of 365 males and 241 females between the ages of 20 and 80 ; 



(3) the admirable series collected by Retzius (:Oo) from the 

 Swedish population, including, after casting out incomplete 

 records, data for 416 males and 233 females between the ages 

 of 20 and 80 ; (4) Matiegka's (:03) Bohemian (Czech) series, 

 which includes records for 372 males and 197 females. In ad- 

 dition to these series a portion of the Boyd-Marshall data ob- 



