132 PHYSIOLOGY. 



folded in a slow and gradual manner, and the intellectual fac- 

 ulties appear in succession only as the structure is perfected. 

 For example, in infancy, the cerebellum forms one fifteenth 

 of the encephalic mass ; in adult age about one sixth. In 

 childhood the middle parts of the forehead preponderate ; in 

 later life, the upper lateral regions are more prominent, 

 which facts are also in accordance with the periods of unfold- 

 ing the knowing and reasoning faculties. 



27. Genius is almost always partial ; that is, men gene- 

 rally have a taste or faculty, for one particular pursuit, or 

 study, in which alone they have the power of excelling. One 

 has a talent for poetry, another for mechanics, another for 

 drawing, music, or mathematics, and that is often developed 

 at a very early age, and without the advantages of educa- 

 tion, or particular instruction, and these persons may, in all 

 other pursuits, be below mediocrity. Indeed, nothing is 

 more common than to see in the same individuals some fac- 

 ulties acute and powerful, while others are feeble and defec- 

 tive ; having an extraordinary memory for dates, words, 

 places, &c., while as to other things it is deficient. Such 

 facts are not easily explained on the scheme of a single in- 

 tellectual faculty, and a single organ devoted to its exercise. 



28. It is an observation of common notoriety, that when 

 the mind is fatigued with one kind of occupation or study, it 

 can engage, with vigour, in one of a different kind, requiring 

 the exercise of different faculties ; and thus, instead of fa- 

 tiguing, actually acts as a restorative. Could this happen, . 

 unless there were a plurality of faculties and organs of the 

 intellect ? 



29. The phenomena of partial idiocy and partial insanity 

 are at variance with the doctrine of a single organ of mind. 

 We often see persons in a state of monomania, that is,\they 

 are rational enough on all subjects but one ; but in relation 

 to that, they are entirely mad.) Now, if the brain be suffi- 

 ciently sound to manifest all the other faculties in their per- 

 fect state, why is it not also able to manifest this ? 



