To find excellencies, however dispersed; to discover beauties, however concealed by the multitude of defects with which they are surrounded, can be the work only of him, who, having a mind always alive to his art, has extended his views to all ages and to all schools, and has acquired from that comprehensive mass which he has thus gathered to himself--a well-digested and perfect idea of his art, to which everything is referred. Like a sovereign judge and arbiter of art, he is possessed of that presiding power which separates and attracts every excellence from every school; selects both from what is great, and what is little; brings home knowledge from the East and from the West; making the universe tributary towards furnishing his mind, and enriching his works with originality and variety of inventions. Thus I have ventured to give my opinion of what appears to me the true and only method by which an artist makes himself master of his profession; which I hold ought to be one continued course of imitation, that is not to cease but with his life. Those, who either from their own engagements and hurry of business, or from indolence, or from conceit and vanity, have neglected looking out of themselves, as far as my experience and observation reaches, have from that time, not only ceased to advance, and improve in their performances, but have gone backward. They may be compared to men who have lived upon their principal till they are reduced to beggary, and left without resources. I can recommend nothing better, therefore, than that you endeavour to infuse into your works what you learn from the contemplation of the works of others. To recommend this has the appearance of needless and superfluous advice; but it has fallen within my own knowledge, that artists, though they were not wanting in a sincere love for their art, though they had great pleasure in seeing good pictures, and were well skilled to distinguish what was excellent or defective in them, yet have gone on in their own manner, without any endeavour to give a little of those beauties, which they admired in others, to their own works. It is difficult to conceive how the present Italian painters, who live in the midst of the treasures of art, should be contented with their own style. They proceed in their commonplace inventions, and never think it worth while to visit the works of those great artists with which they are surrounded.