Serous transudates from free surfaces are sometimes spoken of as serous _catarrhs_; when into cavities, as _dropsies_; when into tissues, as _edema_; when occurring beneath the epidermis they form _serous vesicles_ or _blebs_ or _bullæ_. _Fibrinous_ exudation refers to the fluid which coagulates soon after its exit from the vessels within those spaces into which it has oozed. When flocculi of coagula float in serous fluid it is known as a _serofibrinous_ exudate. Pure fibrinous exudate occurs rarely, save in and upon mucous membranes. The extent to which exposure to the air is responsible for the firm coagulation of the fibrin previously held in solution is uncertain. The most potent factors in producing such coagulation are bacteria, but it is not yet disproved that coagulation may occur without their aid. When such coagulation occurs upon the surface of a mucous membrane it has been spoken of as _croupous_. When the epithelial covering as well as the basement membrane, and often the submucous tissues, are involved, so that the membrane cannot be stripped off without tearing across minute bloodvessels, the exudate has been known as _diphtheritic_. These terms may possibly be still retained in an adjective sense as implying the exact location of a surface exudate, but are scarcely to be used in any other significance. The following table illustrates significant differences whose full importance cannot be impressed before a study of inflammation has been carefully entered upon: _Hyperemic Transudates._ _Inflammatory Exudates._ Poor in albumin. Rich in albumin. Rarely coagulate in the tissues. Usually coagulate in the tissues. Contain few cells. Contain numerous cells. Low specific gravity. High specific gravity. Contain no peptone. Contain peptone (product of cell disintegration). TREATMENT OF CONGESTION AND HYPEREMIA. These disturbances are to be combated, first of all, by insisting upon _physiological rest_. This, perhaps, is the most important measure of all. The profession is indebted to Hilton for the decided advance which he made in the treatment of congestive and inflammatory affections by insisting upon this principle in his celebrated work on _Rest and Pain_, which every young practitioner should read. Aside from this first and underlying principle, the treatment must, in some measure at least, be based upon the time at which we are called upon to treat the case. If seen at once, before exudation has been excessive or the other disturbances marked, we may carry out a certain line of treatment for the purpose of limiting all these unpleasant features. On the other hand, if seen late, when exudation has been copious and when pain and other disturbances are due to its presence, a distinctly different course will be adopted.