Read it through once

"He has, perhaps, the same pleasure as a physician who sets his finger upon the unsound parts of a healthful body. The physician's pleasure is not aesthetic; it is scientific. He loves the infirmity because it gives him an opportunity of practising his art. So with the critic. He discovers the defects because he wishes to rectify them. But in his zeal he forgets that art is not a science. It is not diagnostic. It is creative. He analyser is not equal to the artist. The critic who can create is of course a poet himself; he is no mere critic, but another maker. He belongs to that small class of men who can both produce and understand production."