Although the _external_ application of cold was not often employed in the hot stage of fever, until within the last thirty years, yet the administration of cold _drinks_ appears to have been practised by the ancients, as an expedient to produce perspiration. Galen, and his immediate disciples, as well as the physicians of the sixteenth century, seem to have frequently administered cold water for the purpose of exciting sweat in fevers.[162] Celsus also describes the beneficial effects which arise from copious draughts of cold water in ardent fevers, “fereque post longam sitim et vigiliam, post multam satietatem, post infractum calorem, plenus somnus venit, per quem _ingens sudor effunditur_, idque præsentissimum auxilium est.”[163] Cold water, when introduced into the stomach in the hot stage of fever, must produce its diaphoretic effect through the sympathetic relation which subsists between that organ and the skin. Nauseating doses of _Antimony_, and of other emetics, occasion a relaxation of the surface from the same mode of operation, and in this latter case, if the force of the circulation be at the same time increased by tepid diluents, the diaphoretic effect is more certain and considerable. _Alcohol_, _Guaiacum_, and other powerful stimulants, produce their effects by merely accelerating the circulation; but in employing such remedies for the purpose of exciting sweat, we must be careful to adapt them to the circumstances of the case, and to the degree of action which prevails. In all febrile diseases attended with much increased heat, or connected with local inflammation, diaphoretics of this description must be very cautiously administered, for by accelerating the circulation they might counteract any benefit which they would otherwise confer by relaxing the vessels of the skin. In the whole history of medical opinions there is scarcely a theory which has proved so fatal in its practical applications as that maintained by Van Helmont, and his disciples, viz. that _acute diseases were to be cured by expelling some morbific matter, after its proper concoction_—a theory which suggested the administration of the most stimulating sudorifics, together with high temperature[164] in every grade of febrile exacerbation. The fatal effects of such a practice during the seventeenth, and early parts of the eighteenth centuries, are incalculable, and may be very satisfactorily contrasted with the beneficial results which have accrued, in the same diseases, in the present age, from the use of diaphoretics of the refrigerant kind.