The individual medicines which compose the class of DIAPHORETICS vary no less in their primary operations, as the synoptical arrangement at _page 99_ very fully exemplifies; thus, in the cure of intermittent fevers, diaphoretics are useful both in the paroxysm, and during the intermission; in the first case they shorten its duration; in the second they support the tone of the extreme vessels, and prevent its recurrence; but in these opposite states of disease a very different kind of diaphoretic is required—to fulfil the first indication, a cooling and relaxing one is necessary; to answer the second, the stimulating diaphoretic is exacted; the one may be said to _solicit_, the other to _extort_, perspiration. So again EMMENAGOGUES can only be considered relative agents, since the suppression of the catamenia may depend upon, or be connected with, very different states of the system; in some cases with a diminished, and in others with an increased state of excitement; for on many occasions the suppression of the menses is the effect, and not the cause of disease; _Boerhaave_ has very justly observed, that it is a most dangerous error to ascribe all the diseases of young females to a retention of the catamenia, which often do not appear because the patients are disordered from other causes. If, therefore, we were to attempt a combination of the several medicines which have gained reputation as _Emmenagogues_, it is very obvious, that we should bring together an assemblage of adverse and incompatible remedies; nor would the physician be less inconsistent were he to combine EXPECTORANTS, without a due regard to their modes of operation; it is only necessary to observe their classification, as presented at page 102, to become satisfied how greatly the success of such remedies must depend upon their scientific adaptation to each particular case.