LYTTON STRACHEY tells the following story. In intervals of relaxation from his art, the painter Degas used to try his hand at writing sonnets. One day, while so engaged, he found that his in- spiration had run dry. In desperation he ran to his friend Mallarme, who was a poet. "My poem won't come out," he said, "and yet I'm full of excellent ideas. " "My dear Degas," Mallarme retorted, "poetry is not written with ideas, it is written with words. "...