The general plan I have followed in my treatment of the subject is sufficiently explained in the Introduction; while a perusal of the text will show in what relation my investigations stand towards those of my predecessors, and at the same time to what extent these have been made use of, or indeed could be made use of, in my work. Owing to the very nature of the subject the Survey as a whole was bound to assume a critical character, dealing as it does not solely with the history of the Disease, but also with the examination of an extensive array of views and opinions already formulated. The conduct of this examination I leave the reader to judge of; but I believe I can confidently assert it was always the matter, never the man, that I subjected to critical treatment. Accordingly I laid little stress on brilliant results, and made no effort to conceal lack of facts by dazzling hypotheses; instead I made it my supreme object to come at the truth as near as possible, and preferred to confess my ignorance, if the helps and authorities I had at my disposal failed me, rather than advance propositions the baselessness of which a sober criticism is only too soon in a position to demonstrate. “I imposed this law on myself—to believe no man’s mere assertion; to depend on original authorities; to look at every passage with my own eyes, and read it in connexion with its context; to pick out the plain fact observed from the Chaos of hypotheses, and to accept as exact only what I could deduce from the authorities myself and see to be the evident purport of the observation,—absolutely unconcerned how each arbitrary theory might be affected or the sacrosanct authority of such or such a Scholar stand or fall. Why should we deem great men infallible? why find it impossible to honour them and yet dissent from them in opinion?—I felt I owed to my reader a corresponding impartiality in statement of the facts and arguments based upon them. If I was determined to take nothing on trust, but to examine and see for myself, I could not reasonably demand faith from the reader and refuse to communicate to him the proofs and original documents I had drawn upon. It was no case of mere quotation from books,—I was bound to lay open the original evidence for his inspection.” These words of Hensler’s I took as my guiding-principle, and if I have deviated from their standard in the Third Section, this only happened because the greater part of the passages there quoted have been repeatedly handled by my predecessors, and I feared to increase the bulk and consequently the cost of the Book to the prejudice of the reader.