Mr. Channing was appointed Dexter Lecturer on Biblical Criticism in Harvard University, in 1812, but his health did not allow him to prepare a course of lectures, and he resigned the appointment the next year. In 1813 he was elected a member of the Corporation, at which board he retained a seat till 1826. The University conferred on him the honorary degree of D. D. in 1820. Dr. Channing first appeared as a controversial writer in 1815, when he addressed his letter to Rev. S. C. Thatcher, “on the aspersions contained in a late number of the Panoplist, of the ministers of Boston and the vicinity.” This led to a public correspondence between him and the Rev. Dr. Worcester, of Salem. In 1819 he preached the sermon at the ordination of Mr. Sparks, at Baltimore, which produced the letters of Professor Stuart, and of Drs. Wood and Ware. In this sermon he took that position in behalf of Unitarianism, which he defended in many subsequent discourses, on public occasions, and in his own pulpit. Dr. Channing being very feeble, embarked for Europe, in May, 1822, and returned home in August, 1823. During his absence, he visited Great Britain, France, Switzerland, and Italy. In the autumn of 1830 he was again compelled, by his state of health, to leave the United States, and passed the winter of 1830-31 in St. Croix. One or two subsequent winters he spent in Philadelphia. He probably derived permanent benefit from this absence to Europe, but still there was such an habitual want of vigor in his system, that, soon after his return, he desired an assistant in his ministry; and a colleague was settled in 1824. From this time he continued to officiate in the pulpit, with more or less frequency, as his strength permitted, till 1840, when he requested the society to release him from all obligation of professional service, though he desired to retain the pastoral connexion towards them. As his mind was relieved from the pressure of ministerial engagements, his attention was more and more given to the aspects which society, in its opinions, usages, and institutions, presents to the Christian philanthropist. He was led, by his interest in these subjects, to communicate to the public, at different times, his thoughts on questions of immediate urgency, involving high moral considerations, and devoted a large part of his time to an examination of the light which Christianity throws upon practical ethics.