The Basal Ganglia 105 



and throughout all classes of vertebrates, in- 

 cluding human beings; in fact, it constitutes 

 a kind of matter which has passed through long 

 ages of evolutionary changes, and has thus 

 assumed a form which when brought into play 

 becomes manifest in instinctive action. In the 

 higher classes of animals by appropriate treat- 

 ment, the structural arrangement and functions 

 of this part of the brain may be modified ; one 

 of the main objects of education is to effect this 

 purpose, and thus to improve the innate disposi- 

 tion or character of an individual. 



Almost every part of the walls of a lamprey's 

 fore-brain contains nerve fibres proceeding 

 from the olfactory lobes, and terminating in 

 primordial cortical cells, " by means of which 

 smell impressions pass indirectly through the 

 intermediation of another part of the hemi- 

 spheres " l ; thus showing a disposition towards 

 the differentiation on the part of certain of the 

 nervous elements of the hemispheres of the 

 brain in this, the lowest genera of true verte- 

 brates. In the ascending classes of animals 



1 Prof. Elliot Smith's Arris and Gale Lectures, reported in the 

 Lancet for January i5th, 1910, p. 150. 



