When the artist is once enabled to express himself with some degree of correctness, he must then endeavour to collect subjects for expression; to amass a stock of ideas, to be combined and varied as occasion may require. He is now in the second period of study, in which his business is to learn all that has hitherto been known and done. Having hitherto received instructions from a particular master, he is now to consider the art itself as his master. He must extend his capacity to more sublime and general instructions.