252 VESTIGES OF THE 



mena of the new science of photography, when images 

 impressed by reflection of the sun's rays upon sensitive 

 paper are, after a temporary obliteration, resuscitated on 

 the sheet being exposed to the fumes of mercury. Such 

 are the phenomena of memory, that handmaid of intel- 

 lect, without which there could be no accumulation of 

 mental capital, but an universal and continual infancy. 

 Conception and imagination appear to be only intensities, 

 so to speak, of the state of brain in which memory is 

 produced. On their promptness and power depend most 

 of the exertions which distinguish the man of arts and 

 letters, and even in no small measure the cultivator of 

 science. 



The faculties above described— the actual elements of 

 the mental constitution — are seen in mature man in an 

 indefinite potentiality and range of action. It is different 

 with the lower animals. They are there comparatively 

 definite in their power and restricted in their application. 

 The reader is familiar with what are called instincts in 

 some of the humbler species, that is, an uniform and un- 

 prompted tendency towards certain particular acts, as 

 the building of cells by the bee, the storing of provisions 

 by that insect and several others, and the construction 

 of nests for a coming progeny by birds. This quality is 

 nothing more than a mode of operation peculiar to the 

 faculties in a humble state of endowment, or early stage of 

 development. The cell formation of the bee, the house- 

 building of ants and beavers, the web-spinning of spiders, 

 are but primitive exercises of constructiveness, the faculty 

 which, indefinite with us, leads to the arts of the weaver, 

 upholsterer, architect, and mechanist, and makes us often 

 work delightedly where our labours are in vain, or nearly 

 so. The storing of provisions by the ants is an exercise 



