On the other hand, the discovery of anesthesia, which made possible an enlarged and humane use of animals for experimental inquiry, and such illuminating reports and investigations as those of Claude Bernard, Helmholtz, Virchow and Ludwig were giving a great impetus to the investigation of bodily processes and functions, and a study of these was a possible next step in James's evolution. He had already been unusually well grounded in comparative anatomy by Agassiz and Jeffries Wyman. He was gravitating surely, even if he did not yet realize it clearly, toward philosophy. Whenever he more or less consciously projected himself forward, it must have seemed to him that the examination of processes in the living body, for which he was already prepared, might be related, in an enlightening way, to the philosophic pursuits that were beginning to invite him. Physiology therefore commanded both his respect and his curiosity, and he turned in that direction rather than toward what he then saw surgery and the practice of internal medicine to be. During the winter of 1866-67 he lived with his parents in the house[32] in Quincy Street, Cambridge, in which they had settled themselves, and worked regularly at the Medical School. He had come back from the year of mere animal existence on the Amazon in excellent physical condition. Of the four letters which follow, two were written to Thomas W. Ward, who, it will be remembered, had been a member of the Amazon Expedition, and who, after getting back to New York, had entered the great Baring banking house of which his father, Samuel Ward, was the American partner. O. W. Holmes, Jr., will be recognized as the present Associate Justice of the United States Supreme Court. In no one did James find more sympathetic philosophic companionship at this period. _To Thomas W. Ward._ BOSTON, _Mar. 27, 1866_.