3/2 'Journal of Comparative Neurology and Psychology. 



he finds that the 0.56 power of the body weights, gives very nearly 

 the brain weights as observed. The 0.56 power of the body 

 weights represents the relation of the brain weights found by 

 Dubois ('98) to subsist between animals of like form, but dif- 

 ferent species. Leaving aside at this time any discussion of La- 

 picque's general result, I wish merely to point out that the brain 

 weights according to sex, as shown by these data of Lapicque, 

 are so related that when the body weight of the female is raised to 

 that of the male, it calls for approximately the same brain weight 

 as is found in the male. 



We may conclude, therefore, that in both rat and man the brain 

 weight is nearly the same in both sexes, when the body weights are 

 the same, such small difference as is still found being in favor of 

 the male, but at the same time probably open to further reduction. 



If we turn now to the spinal cord, a direct comparison of the 

 weights according to sex is blocked in man by the absence of suf- 

 ficient data. Some light, however, can be obtained by examin- 

 ing in the case of man the ratio 



Brain weight 

 Spinal cord weight 



Mies ('93) gives the following: 



Age. 



Male. 



No. of 



cases. 



Ratio 



B.W. 



s.c.w. 



Female. 



No. of 

 cases. 



Ratio 



B.W. 



Birth . . . 

 Maturity 



116.42 



51-33 



113. II 



49-47 



which shows that in proportion to the brain weight both at birth 

 and at maturity the weight of the spinal cord in the male is less, 

 i.e., gives a higher ratio than in the female. 



In a series of eight comparisons, extending in age from one 

 month to 6^ years, and based on 35 males and 38 females, Pfister 

 ('03) finds the proportional value of the spinal cord weight in each 

 of the eight comparisons, to be less in the^male, indicating accord- 

 ing to the average of the ratios, about 4 per cent of difference in 

 favor of the spinal cord in the female. From what has been said 

 concerning the weight of the brain and of the spinal cord in the 



