With this paper Lowell took leave of political writing for a long time.[29] When next we meet him in this field it will be after certain practical experience in the field of politics has given its own color to his mind. Now, as if he had shaken off an irksome task, he turned more entirely to literature. The next three or four years were occupied, as the calendar of his published writings shows, with diligent excursions in letters, both in prose and verse. The article on Percival which appeared in the _North American_ for January, 1867, was an amusing treatment of a commonplace book, but it was worth preserving for its humorous presentation of the touchstones of genuine poetry; and from what Lowell says in his letters of the slight personal acquaintance he had with Percival, it is quite likely that the encounter gave a little fillip to his interest; yet one may be permitted to look a little more closely and find in Lowell’s characterization of the poetic temperament and sentimentalism, when laid bare through the absence of the clothing of sound sense and humor, a distant reflection on weaknesses of which he was conscious when in the depressed mood. There was an assimilating faculty which he possessed that led him, when reading lives and records especially of literary careers, to suffer somewhat as the young student of medicine who is never quite sure that he is not acting as a sort of proxy for the cases whose diagnosis is laid before him. It is curious to find Lowell, when engaged on Lessing’s life and works, which he reviewed in the April _North American_, writing to Mr. Norton:[30] “I find somewhat to my surprise from his letters that he had the imaginative temperament in all its force. Can’t work for months together, if he tries, his forehead drips with _angstschweiss_; feels ill and looks well--in short, is as pure a hypochondriac as the best. This has had a kind of unhealthy interest for me, for I never read my own symptoms so well described before.” And the article itself, if one reads it with Lowell’s thought about himself in mind, becomes a curiously parallel record, even to external circumstances, of the two men. It would, of course, be untrue to say that Lowell was thinking of himself when he was writing of Lessing, but I cannot help suspecting, as I read the article, that there was a subconsciousness which gave a force to certain passages, and that Lowell’s interest in his subject was heightened by the plucking at his sleeve of his own memories and ambitions.