upon my performances in this line, I have certainly spared no pains to make myself well acquainted with the true doctrines of my author, and that for this purpose I have consulted all the best authorities to which I could obtain access, from the commentaries of Apollonius and Galen down to the learned labors of several continental scholars, my contemporaries, especially Dr. Ermerins, of Holland, and MM. Littré and Malgaigne, of France. I flatter myself it will also be admitted, that I have further collected from a variety of sources, a considerable store of valuable material, for which I am in nowise indebted to any of my predecessors in the same field of research. Considering how scanty all the information is which the English language can supply on many questions connected with the medical literature of the ancients, I have judged it necessary to enter into a discussion of several of those subjects, in order to prepare my readers for understanding the doctrines of my author. These are contained in the Preliminary Discourse, and will be found to relate principally to the origin of Grecian Medicine, to the Biography of Hippocrates, and an analysis of the works which bear his name, and to an exposition of the principles of the Physical Philosophy which form the basis of most of the hypotheses which occur in the Hippocratic Collection. Having bestowed much pains on the illustration of the philosophical tenets of the ancients, I shall feel anxious to learn how far the judgment pronounced by me on various controverted points is approved of by persons possessing the necessary degree of information to enable them to form a correct estimate of them, along with a proper degree of candor in judging between the conventional opinions of the present time, and those which prevailed in so remote an age. That I have imposed upon myself a very serious additional task, by engaging not only to give a true version of the language of my author, but also to expound his opinions, and place them, so to speak, in juxtaposition with those of the present age, will be readily admitted; and I have reason perhaps to apprehend, that I have thereby exposed myself to the strictures of a certain class of critics, who have formed to themselves a very different ideal of the duties of a translator, fancying that he ought merely to concern himself with the words of the original author, and not venture to sit in judgment on the doctrines. I shall not attempt, however, any formal defense of the method which I have pursued, but may be allowed to remark, that, if I shall be found to have failed in satisfying the reasonable expectations of such readers as are sincerely desirous of becoming familiarly acquainted with the opinions of an author, whom I verily believe to be the highest exemplar of professional excellence which the world has ever seen, it is not from want of zeal in the discharge of the arduous duties which I had undertaken.