AN ENQUIEY INTO THE FOEMATION OP HABIT IN MAN. 165 



In studying the relation of the intellectual faculties to cerebral 

 development, various considerations mast be taken into account ; 

 among them individual circumstances and surroundings, heredity, 

 national and racial diffei^ences, for the circumstance has to be 

 borne in mind that such differences do exist in a degree as marked 

 as are the distinctive physical characteristics which divide them 

 ethnically. The relation in which the aspect of the general 

 subject as here presented stands to others connected with 

 pauperism and criminality among populations opens up a question 

 so extensive in its bearings that it can only be thus alluded to on 

 this occasion. 



Adverting to the subject of what have been called motor areas 

 of the brain, I remark further that phenomena observable in 

 disease are in many respects at variance with deductions arrived 

 at by artiticial methods of investigation. Other circumstances 

 point to the necessity for enlarging, if not for otherwise modifying 

 that theory. For example, at page 137 of the excellent paper before 

 us, allusion occurs to the " mapping out " of such areas, in the 

 apparent sense that particular muscular movements are directly 

 connected with and dependent upon the regions so indicated ; at 

 page 143 the circumstance is mentioned that "pigeons can fly after 

 the removal of the cortex of the brain ; fi'Ogs similarly treated can 

 balance themselves on a board slowly turned round, and will 

 croak." The whole class of movements to which the name of 

 " reflex " is given tend to indicate their own dejiendence upon, 

 cerebral motor areas. 



Facts such as the following are not to be ignored in connection 

 Avith those remarks, namely, the amphioxus among fishes, and all 

 the invertebrate animals are destitute of a true brain, and yet all 

 necessary functions take place in them. Cases of acephalous 

 children are recorded in which the functions of respiration were 

 performed, and various movements of the limbs took place. Cases 

 are even on record in which though during life no characteristic 

 symptoms were present, post mortem examination revealed 

 extensive cerebral disease. 



At page 146 such subjects are discussed as " natural instincts," 

 "artificial reflexes," "physical memory," "psychical habit," &c. 

 In respect to all of which, unfortunately for myself, I am 

 unable to appreciate the precise measure of significance intended 

 to be conveyed by them respectively. No such difficulty occurs 

 to me in regard to the statement at Jiage 147 having reference 



