Anatomical Characters of the Human Brain. 5 



tliat in individual specimens this was not always the case, "so dass 

 wir nocli keinesweges in der Lage sind, von eiuem ^gesetzmassigen 

 Verhalten' wie es Riidinger tut, sprechen zu konnen." My own ex- 

 perience confirms Waldeyer's, for while the male of twin pregnancies 

 is often markedly larger than the female it is by no means always 

 so. Of course, this does not mean that the frontal lobe is relatively 

 larger in the male. 



More extensive measurements were made by Passe t^ who studied 

 with great care the brains of 17 adult males and 12 females. He 

 found the position of the central sulcus much the same in both sexes, 

 if anything a little further back in the male than in the female. He 

 shows by a diagram (Fig. 6) that there is a great deal of variation 

 of the position of this sulcus in different brains, its angle with the 

 sagittal plane ranging from 46° to 79°. The average is 62° for the 

 male and 64° for the female. He states that the central fissure 

 is shorter and straighter in the female and lies farther forward. 

 Although his work was done with the greatest of care his methods 

 are too crude, the number of specimens studied too small, and the 

 degree of variation so great, that nothing is proved regarding the 

 relative size of the frontal lobe in the two sexes. 



Eberstaller^^ in the discussion of the above question in his excel- 

 lent monograph on the frontal lobe concludes that there are no dif- 

 ferences due to sex in the angle that the central sulcus of the brain 

 makes with its sagittal median plane. His measurements included 

 300 hemispheres and he found that the above mentioned angle varies 

 constantly between 70° and 75°. He further found that the central 

 sulcus when extended intersected the sagittal border of the mantle 

 at 65.4 per cent of the distance from the olfactory trigonum to the 

 occipital pole in men and at 66 per cent in women. If this means 

 anything it indicates that the frontal lobe in the brain of women 

 is relatively larger than it is in men. The objections to the con- 

 clusions of Huschke and Passet regarding the percentages of brain 

 in front and behind the central sulcus are fully discussed by Eber- 

 staller, who points out the weaknesses of their observations as well 

 as the objections to their conclusions. 



*Passet. Arch. f. Anthropologie, XIV, 1883. 

 '"Eberstaller. Das Stirnhirn. Wien, 1890. 



