Twenty years have now elapsed since the first Edition of this Book made its appearance. During this period, the Author, having been in constant practice, has taken occasion to improve several articles, which were with less accuracy inserted in the more early impressions. For this he has been censured by some, but the more candid and discerning must approve his conduct. It would be unpardonable in an Author to suffer an error in a book, on which health and life may depend, to stand uncorrected; nor would it be much less so to perceive an omission, and leave it unsupplied. His improvements, however, are not the result of mercenary views. The same principle which prompted the Author to write the Book, will ever induce him to improve it to the utmost of his power. The Author has indeed to regret, that the limits of one volume preclude many interesting observations, and likewise deprive him of the pleasure of inserting a number of very useful remarks made by his learned and ingenious friend Doctor DUPLANIL, of Paris, who has done him the honour of publishing an elegant translation of this Work, in five volumes octavo, accompanied with an excellent commentary. The improvements of the later editions are chiefly inserted in the form of notes. These are intended either to illustrate the text, or to put people on their guard in dangerous situations, and prevent fatal mistakes in the practice of medicine, which it is to be regretted are but too common. Some attention has likewise been paid to the language. Where that was either inaccurate or obscure, as far as was practicable, it has been corrected. Indeed, the Author has all along endeavoured to observe such simplicity and perspicuity in his style as might enable the reader clearly to understand it: a circumstance of the utmost importance in a performance of this nature. Although the DOMESTIC MEDICINE was never intended to supercede the use of a physician, but to supply his place in situations where medical assistance could not easily be obtained; yet the Author is sorry to observe, that the jealousies and fears of the Faculty have prompted many of them to treat this Work in a manner altogether unbecoming the professors of a liberal science: notwithstanding their injurious treatment, he is determined to persist in his plan, being fully convinced of its utility; nor shall interest or prejudice ever deter him from exerting his best endeavours _to render the Medical Art more extensively beneficial to_ MANKIND.