406 On Genius. 
according to our theory, they both arise from 
an original susceptibility of temperament) 
but’ because they are developed by habits of 
avery different kind; and, when these ha- 
bits are once formed, it is difficult to shake 
them off, and assume others which are al- 
most incompatible with them. It is a con- 
stitutional warmth and sensibility of mind, 
which fits us to bestow a profound attention, 
and to feel a lively interest; in this lies the 
foundation of Genius: circumstances will 
decide whether its enthusiasm be directed to 
philosophy, science, literature, or the arts. 
The determinaton may be given at an age, 
to which the record of the biographer does 
not ascend; and the associations of interest 
and delight, thus early awakened, may be so 
vivid—and the habits, formed in consequence, 
may be so firmly established and have be- 
‘come so prompt and active, as almost to un- 
fit the mind for any pursuit, but that on 
which its energies and sensibilities have been 
concentrated, and to induce the belief that 
it was born with an original aptitude for it.(q) 
(q) The effects of close and continued attention to one subject almost 
exceed belief. Nil mortalibus arduum est. In the operations of ma- 
nual skill, as evinced by jugglers and some kinds of handicraftsmen, 
they emulate the marvellous results of magic. From a long train of 
‘observations on the appearances of the elements and the minute processes 
