Whatever be the phenomena of fever they depend upon certain states of the organs. Whatever be the noxious agents or the exciting causes of the disease, and however they operate, they can induce the disease only by bringing about a certain condition in a certain number of organs, the individual events constituting the disease being nothing but certain changes in these organs. It is therefore of paramount importance to ascertain what the organs are which are implicated; what the conditions are which are induced in them; what organ sustains the first assault and what organs are attacked in succession. The pathology about to be laid before the reader will demonstrate the first two points: the establishment of the last two will be attempted by an examination of the history of the cases. Without doubt the life or death of the patient depends upon these conditions of the organs. In a practical point of view therefore, this is the kind of knowledge with which it is of the greatest importance that the practitioner should be familiar. Some of these conditions are indicated by certain signs during life: some of these indications are obscure, and may be easily overlooked or mistaken by those who have not acquired an accurate and extensive acquaintance with the disease. On the other hand, there are external appearances which are extremely apt to suggest a false notion of the state of the internal organs. These fallacious appearances are sure to lead those whom they deceive into a mistaken, often into a mortal practice. Certain conditions of vital organs, if allowed to remain long, will terminate in fatal changes of structure. Certain remedies, if applied in due season and with due vigour, are capable of removing those conditions. Life therefore must sometimes depend upon the power of making this diagnosis with accuracy. Of some of these conditions, the diagnostic marks are clear and certain; those which indicate other conditions, in the present state of our knowledge, are obscure and uncertain. I have thought no labour too great to put the reader in possession of all that I have been able to ascertain with regard to this most important part of the subject. In the attempt to communicate this information, I am conscious that I may incur the charge of tediousness, on account of the number of repetitions which occur, and which I have allowed to remain because I could see no means of removing them without sacrificing clearness to brevity. Elegance and conciseness, in a work of this nature, ought not for a moment to be considered if they endanger its practical usefulness. A knowledge of the condition of the internal organs, in fever, can alone guide us to a rational and successful treatment of this most dangerous disease. It is only by examining the body after death that we can acquire this information: it is only by observing the symptoms during life and comparing them with the morbid appearances after death, that we can