Take Teniers, with his delicious silvery tones and crisp touch, the man who paid his dinner with a picture, and painted his picture first while the dinner was cooking: compare David Wilkie with him, and see how David Wilkie shrivels up with heat before the cool tones of David Teniers the younger. Consider Cuyp, with his precise touch; Van Eyck, the father of oils, with his quaint mediævalism and patient symbolism; Weyden, as in 653, with his rigid adherence to facts; Quintin Matsys, with his hard high finish; Rubens, the lavish and exuberant; Vandyke, the refined; Gerard Dow, with his exquisite delicacy; Frans Hals, with his vigorous handling and open colouring; and lastly, the greatest master of all, the immortal Rembrandt, whom, for his portraits, chiaroscuro, colour, and vigour, I cannot find words to praise enough. No one has a right to speak as an art critic about pictures unless he can paint a picture himself, or at least is able to copy faithfully the picture which he criticises. I trust that I may say, by way of apology for my present free criticism, without being carped at as a vain boaster, that I have painted original pictures in landscape, seascape, and composition. I can also say that I have copied some of the masters whom I recommend, and can copy any picture ever painted, provided I have the leisure; and also I can tell you, after I have copied a picture carefully, exactly how the master painted his picture, the number of times he worked over it, and sometimes also not only the time he took to do it, but also his moments of hesitation and inspiration, depression and artistic exultation. But before I can tell you all these secrets about the mystic dead, I must first study his work by copying it; it would be only guesswork were I to content myself with looking at his canvas or panel; and what I am unable to do with my long and extensive training as a painter, I defy any non-painting art-critical dilettante to be able to do. John Ruskin qualified himself as an art critic by learning to draw and paint, and when bigotry or bilious bad temper does not interfere with his critical vision, he stands, and must for ever stand, pre-eminent amongst art critics. No human being, however gifted he may be, is able to see colours or any other merit in either a picture or a book when he has a fit of indigestion or dyspepsia. The blue appears green, the clouds heavy, the firm lines shaky, the composition vile, the chiaroscuro gloomy, and the general colours dirty and unsatisfactory. A proper pill taken in time by the critic has often saved the reputation of the painter, poet, or novelist. As one patent medicine advertisement has announced, with a wisdom which should go far with sensible thinkers to recommend the drug: 'Dyspepsia leads more often to the divorce court than vice.'