VISITORS TO a performance by the Kneisel String Quartet in New York City one autumn afternoon in 1894 may well have been distracted from the sonorities of Beethoven by a strangely dressed man in the audience. In contrast to the stylish appearance of the rest of the music lovers, he wore a rumpled corduroy hunting suit, a battered felt hat, rubber boots, and a frayed handkerchief wound round his head and tied under his chin, as if to relieve a toothache. He carried a brown paper sack, which, when placed under the seat, leaked trails of blood on the auditorium floor. Those present may have assumed that here was some Yankee rustic, game bag in tow, who had wandered into the concert hall on impulse, and they would have been absolutely correct. They would not have guessed, however, that the man was Abbott H. Thayer, one of the best known and most highly paid society painters on the Eastern seaboard.