260 SKULL AND BEAIN IN MAN. 



dition of the horizontal depression of the cribriform plate in 

 man. It is the measure of the depression of the anterior ex- 

 tremity of the human cranial axis — i.e., it renders it horizontal. 

 It is intimately related to the vertical position and horizontal 

 relations of the human nasal chambers, orbits, mouth, and 

 lower jaw ; as also to the depth and shortness of the facial 

 portion of the human skull ; and, finally, it is an important 

 element in the examination of abnormal forms of skull, and 

 in ethnological research. 



■o' 



Tlu Brain. 



a. The geometrical relations of the various parts of the 

 skull in man and the animal, to which I have now briefly 

 directed your attention, will, I trust, be sufficient to satisfy 

 you that the subject demands a much more precise method 

 of inquiry than has hitherto been employed ; and, in addition, 

 that it promises results similar in kind to those which we 

 attained by the application of this method to the investigation 

 of the trunk and limbs. 



b. The additional space which is obtained in the human 

 cranium, like the completed areas of the joints in the human 

 limbs, is provided for additional structure and corresponding- 

 extension of functions. But where, as in the former, the 

 additional structures and functions were at once recognisable ; 

 in the brain, on the other hand, we can, in the present phase 

 of science, only recognise the masses added. Of the structure 

 and function of those additional masses we know at present 

 nothing, beyond the little which has been ascertained regard- 

 ing the mechanism and actions of the organ generally. 



c. The anatomy of the masses of the brain is the mere 

 rudiment of the subject — the actual anatomy of the brain is 

 its internal mechanism. Till that mechanism has been ascer- 

 tained in man and the animal, the question as to the human 

 and animal brain cannot be solved, and ought not therefore 



