CHAP. XXL] 



OF THE HUMAN BRAIN. 



403 



and actually denied by others to be a usual condition. 



Some of the latter even affirm that though a difference 



often exists, the superiority in weight is most commonly in 



favour of the right rather than the left Hemisphere. This 



point cannot, perhaps, be definitely decided for the present. 



It is obvious that very great care is needed in making 



the sections through the 



' cerebral peduncles ' 



and* corpus callosum,' 



preparatory to such 



comparative weighings 



of the two Cerebral 



Hemispheres, and also 



that the weighings 



themselves require to be 



made with the greatest 



care. 



(5.) The writer many 

 years ago ascertained 

 that the specific gravity 

 of the Grey Matter 

 from the frontal parietal 

 and occipital Convolu- 

 tions, respectively, is FlG< i 48 . -Posterior Diagrammatic View of 

 Often Slightly higher On DuraMaterwithGreatVenousSinu.es. (Todd.) 

 . , . . The posterior portion of the Cranium and the 



tl)0 left than it IS On posterior arches of the upper spinal Vertebrae are 

 tllP ricrht HemisDhere su PP sed to be removed. , The longitudinal 

 y 6 ' sinus ; t, the 'torcular Herophili,' where longi- 



tllOUgh Such Superior tudinal and occipital sinuses meet, and whence 

 T . , -\ the lateral sinuses (e) diverge. 



density does not neces- 

 sarily exist in each of these regions in the same indivi- 

 dual.* This unexpected result frequently, though not 

 invariably, showed itself, even where every care was taken 

 to get rid of sources of fallacy. Further observations are, 



* See " Journal of Mental Science," January, 1866, p. 493 



D D 2 



