It is easy to spare books in these days of prolific authorship; and I fear it will hardly be considered a sufficient apology for my offering a superfluous book to the public, that I was impelled to do so by the request of partial friends. Yet I wish to say, that these Lectures, composed under many interruptions, were not designed for publication.

As I am fully conscious how imperfect has been my discussion of their topics, I cannot do better than point out a few works which the reader who is interested in such subjects may consult with profit and amusement. A large collection of facts will be found in Dr. Macnish's "Philosophy of Sleep," and a still larger number, intermingled with ingenious speculations, in a work by Dr. Binns, entitled "The Anatomy of Sleep." The physiological relations of the subject are admirably treated by Dr. Carpenter, in an article on Sleep in the Cyclopaedia of Anatomy and Physiology. The philosophical reader will consult, with great satisfaction, a chapter on " Dreaming, Insanity, and Intoxication," in Dr. Holland's "Medical Notes and Reflections," and he will also read with pleasure Mr. Dendy's very elegant volume, entitled the "Philosophy of Mystery." Those who wish to view dreams in their moral and religious aspects, should peruse a little work by Mr. John Sheppard, who brings to this subject the same intellectual refinement, conjoined with the same earnestness of moral purpose, which characterizes his other writings. To the lovers of the marvellous, I recommend Mrs. Crowe's "Night-side of Nature," which abounds in striking and well-told stories; more especially as the following pages will be found to be very sparing of such recitals.

Whether my investigation of the order and relations of the phenomena in sleep and dreams has at all furthered the elucidation of them, I must leave my readers to determine.