402 THE EXTERNAL CONFIGURATION 



on the right side than on the left is by no means clear. 

 It might perhaps be occasioned by the slightly increased 

 length of the left Hemisphere, pressing backwards against 

 the left side of the ' torcular,' and so diverting a larger 

 current of the blood flowing along the longitudinal sinus 

 towards the right. It has been long known, indeed, that 

 the groove in the occipital bone for the right ' lateral sinus ' 

 is often distinctly broader than that for the left sinus,* 



FIG. 147. View of Occipital Lobes and of Cerebellum from behind, showing tho 

 ' Occipital Groove ' at the tip of the righr, Hemisphere. (From a drawing by 

 V. Horsley.) 1, The Groove ; 2, 2, External Perpendicular Fissure, c, c, The 

 Cerebellum. 



thus conclusively showing that in all such cases, at least, 

 the larger blood current is accustomed to pass away from 

 the cranium along this side. 



(4.) The left Hemisphere was said by Dr. Boyd to be 

 generally heavier than the right by nearly half an ounce. 

 This, however, has been questioned by some investigators, 



* See fig. 23 of Gray's " Anatomy " (3rd. Edn.), where this 

 condition is well represented. 



