ON CERTAIN ACQUIRED HABITS. 17 



useful but by no means particularly calculating mem- 

 ber of society. 



The case, however, is typical of others in which per- 

 sons have been found able to do without apparent effort 

 what in the great majority of cases requires a long 

 apprenticeship. It is needless to multiply instances ; 

 the point that concerns us is, that knowledge under 

 such circumstances being very intense, and the ease with 

 which the result is produced extreme, it eludes the 

 conscious apprehension of the performer himself, who 

 only becomes conscious when a difficulty arises which 

 taxes even his abnormal power. Such a case, there- 

 fore, confirms rather than militates against our opinion 

 that consciousness of knowledge vanishes on the know- 

 ledge becoming perfect — the only difference between 

 those possessed of any such remarkable special power 

 and the general run of people being, that the first are 

 born with such an unusual aptitude for their particular 

 specialty that they are able to dispense with all or 

 nearly all the preliminary exercise of their faculty, 

 while the latter must exercise it for a considerable 

 time before they can get it to work smoothly and 

 easily ; but in either case when once the knowledge is 

 intense it is unconscious. 



Nor again would such an instance as that of Zerah 

 Colburn warrant us in believing that this white heat, 

 as it were, of unconscious knowledge can be at- 

 tained by any one without his ever having been 

 originally cold. Young Colburn, for example, could 

 not extract roots when he was an embryo of three 

 weeks' standing. It is true we can seldom follow the 



