The numerous unsuccessful attempts which have been made to present the following work in an English translation, sufficiently attest the very general estimation in which it is held, as well as the difficulty of the undertaking. The task having at last been executed by the united labors of four gentlemen, each well qualified for the portion intrusted to him, the American publishers take much pleasure in presenting to the profession of the United States, this great store-house of pathological knowledge, in a convenient and accessible form. The world-wide reputation of the author and of his work render eulogy superfluous, while the appearance of the translation under the auspices of the Sydenham Society is a guarantee of its fidelity. Under these circumstances, and as subsequent papers and researches of the author have been introduced in their appropriate places by the translators, it has not appeared to the publishers that additions were necessary or desirable to such a work or to such an author, and they have consequently endeavored simply to secure an accurate reprint. For greater convenience of reading and reference, and to lessen the cost, the four volumes have been bound in two, the paging, titles, etc, rendering each complete in itself.

The volumes of the English Edition were not published in their regular sequence, Volume II being issued first, and Volume L last. The reader is therefore referred to Dr. Sieveking's Preface to Volume II, as well as to Dr. Swaine's Preface to Volume I., for some explanation of the work, and of the manner and auspices under which it has appeared.

Philadelphia. August, 1855.