428 



THE BRATN. 



in which must reside more especially the nervous functions which 

 they possess. But this layer of gray matter, in each principal por- 

 tion of the brain, is continuous throughout. There is no anatomical 

 division or limit between its different parts, like those between 

 the different ganglia in other portions of the nervous system ; and 

 consequently such divisions of the cerebrum and cerebellum must 

 be altogether arbitrary in character, and not dependent on any 

 anatomical basis. 



Secondly, the only means of ascertaining the location of the 

 different mental traits, supposing them to occupy different parts of 

 the brain, would be that adopted by Gall and Spurzheim, viz., to 

 make an accurate comparison, in a sufficient number of cases, of the 

 form of the head in individuals of known character. But the prac- 

 tical difficulty of accomplishing this is very great. It requires a 

 long acquaintance and close observation to learn accurately the 

 character of a single person ; and it is in this kind of observation, 

 more than in any other, that we are proverbially liable to mistakes. 

 It is extremely improbable, therefore, that either Gall or Spurzheim 

 could, in a single lifetime, have accomplished this comparison in so 

 many instances as to furnish a reliable basis for the construction of 

 a phrenological chart. 



A still more serious practical difficulty, however, is the following. 

 The different intellectual faculties being supposed to reside in the 

 layer of gray substance constituting the surfaces of the cerebrum 



and cerebellum, they must of course be 

 distributed throughout this layer, where- 

 ever it exists. Gall and Spurzheim 

 located all the mental faculties in those 

 parts of the brain which are accessible 

 to external exploration. An examina- 

 tion of different sections of the brain 

 will show, however, that the greater por- 

 tion of the gray substance is so placed, 

 that its quantity cannot be estimated by 

 an external examination through the 

 skull. The only portions which are 

 exposed to such an examination are the 



Diagram of the BRAIN r* .if*. 3 j fe j portions Q f tbe con . 



shuwmg those portions which are ex- ^r 



posed to examination. vcxities of the hemispheres, together 



with the posterior edge and part of the 

 under surface of the cerebellum. (Fig. 140.) ^ A very extensive 



Fig. 140. 



