These distinctions and names then, though it were easy to raise objections against them, may serve for all useful and practical purposes. They tend to impress upon the mind the great fact that all the modifications of the disease are still only modifications, and do not affect the identity of its nature; and they afford convenient sections under which to detail the symptoms that attend and discriminate the important diversities in degree as they present themselves in practice; to exhibit the condition of the organs upon which those diversities depend, and to explain the treatment which experience teaches to be appropriate to these several states. The present work will be restricted to the consideration of the modifications of fever which we have proposed to designate by the terms synochus, typhus, and scarlatina. CHAPTER III. _Of Synochus: Division into Synochus Mitior and Gravior. Succession of Phenomena in Synochus Mitior. Indications afforded of Disease in the Nervous, Circulating, and Excreting Systems. Progress of Disease consisting in progressive Increase in the Derangement of these Functions. Phenomena of Recovery. On what the Transition of Synochus Mitior into Synochus Gravior depends. Classification according to the different Organs in which the several Affections have their Seat. Hence Synochus Gravior with Cerebral Affection—Subacute—Acute: with Thoracic Affection: with Abdominal Affection: with Mixed Affection._ It has been stated that, for the purpose of forming into distinct groups certain assemblages of symptoms which it is important to distinguish, because they bear an important relation to practice, it will be convenient to divide the synochus, the term by which we propose to designate the common fever of this country, as it presents itself in its mild aspect, into two sections, namely, synochus mitior and synochus gravior. For reasons already assigned, it will likewise be important, in treating of these different modifications of fever, to notice in each both the phenomena which form the assemblage, and the order in which they succeed each other.