1. The question propounded.—The members of the Association under whose auspices the ‘Journal of Mental Science’ is published, having done me the honour to elect me an honorary member of their body, I think I cannot better express my strong sense of the compliment thus paid to me, than by a cordial co-operation with them in their labours for the advancement of mental science. The subject I have ventured with this object to bring under their notice, is one of the highest importance to their professional success; it is to determine how far a mental science in the true meaning of the term science is possible, and capable of practical application to mental pathology, therapeutics and hygiène, and the needs of society in general. For more than twenty-five years, I have carefully studied mental science in these its practical relations, and have from time to time made my views public. My friend Dr. J. S. Bushnan, has questioned the value and validity of those views in the journal, on two recent occasions', with special reference to two of my latest publications.* It appears from his last communication, (‘Journal of Mental Science,’ October, 1861), that he has come to the conclusion that my systematic views elaborated after so much labour and thought, and carefully applied, not only to the practice, but also to the teaching of both the practice of medicine in general, and of psychiatry in particular are, “in no sense practical.” This, to me, startling conclusion, has led me to examine into the mode by which my friend and critic came by the notion, and I find that either he or I must be under a singular misapprehension, both as to what is scientific and practical, and as to how it may be attained. I know of no other method for testing where the error lies, than a comparison of Dr. Bushnan's principles and method with mine, in reference to the objects for which the journal is established. Now Dr. Bushnan states his doctrine very explicitly at the outset.