In this second edition of the following Medical Inquiries and Observations, the reader will perceive many additions, some omissions, and a few alterations.

A number of facts have been added to the Inquiry into the Effects of Ardent Spirits upon the Body and Mind, and to the Observations upon the Tetanus, Cynanche Trachealis, and Old Age, in the first volume; also to the Observations upon Dropsies, Pulmonary Consumption, and Hydrophobia, contained in the second volume.

The Lectures upon Animal Life, which were published, a few years ago, in a pamphlet, have received no other additions than a few notes.

The phÆnomena of fever have not only received a new title, but several new terms have been adopted in detailing them, chiefly to remove the mistake into which the use of Dr. Brown's terms had led some of the author's readers, respecting his principles. A new order has likewise been given, and some new facts added, to the inquiry upon this subject.

In the Account of the Yellow Fever of 1793, many documents, interesting to the public at the time of their first publication, are omitted; and many of the facts and observations, which related to the origin of the fevers of 1794 and 1797, now form a part of a separate inquiry upon that subject, in the fourth volume.

The histories of the yellow fever as epidemics, and of its sporadic cases, have been published in the order in which they have appeared in Philadelphia, to show the influence of the weather upon it, and the impropriety and danger of applying the same remedies for the same epidemic, in different and even successive seasons. The records of the first cases of yellow fever, which have appeared in each of the twelve years that have been noticed, are intended further to show the inefficacy of all the means, at present employed, to prevent its future recurrence.

In the fourth volume, the reader will find a retraction of the author's former opinion of the yellow fever's spreading by contagion. He begs forgiveness of the friends of science and humanity, if the publication of that opinion has had any influence in increasing the misery and mortality attendant upon that disease. Indeed, such is the pain he feels, in recollecting that he ever entertained or propagated it, that it will long, and perhaps always, deprive him of the pleasure he might otherwise have derived from a review of his attempts to fulfil the public duties of his profession.

Considerable additions are made to the facts and arguments in favour of the domestic origin of the yellow fever, and to the Defence of Blood-letting.

The Account of the Means of Preventing the Usual Forms of Summer and Autumnal Disease, appears for the first time in this edition of the author's Inquiries. Part of the facts intended to prove the yellow fever not to be contagious, were published in the sixth volume of the New-York Medical Repository. The reader will perceive, among many additions to them, answers to all the arguments usually employed to defend the contrary opinion.

The Inquiry into the Comparative State of Medicine, in Philadelphia, between the years 1760 and 1766, and 1805, was delivered, in the form of an oration, before the Medical Society of Philadelphia, on the 18th of February, 1804. Some things have been omitted, and a few added, in the form in which it is now offered to the public.

If this edition of Medical Inquiries and Observations should be less imperfect than the former, the reader is requested to ascribe it to the author having profited by the objections he encouraged his pupils to make to his principles, in their inaugural dissertations, and in conversation; and to the many useful facts which have been communicated to him by his medical brethren, whose names have been mentioned in the course of the work.

For the departure, in the modes of practice adopted or recommended in these Inquiries, from those which time and experience have sanctioned, in European and in East and West-Indian countries, the author makes the same defence of himself, that Dr. Baglivi made, near a century ago, of his modes of practice in Rome. “Vivo et scribo in aere Romano,” said that illustrious physician. The author has lived and written in the climate of Pennsylvania, and in the city of Philadelphia.

November 18th, 1805.