(From concoquo, to digest). Concoction. It is generally understood to be such a change upon the morbid matter, by the power of nature, generally with assistance of art, as renders it fit for separation from the healthy parts of our fluids, and to be thrown out of our bodies. But this doctrine, at least in fevers, is certainly false. That morbid matter, when it exists, passes off from the blood in its pristine state, appears from the matter of the small pox and measles, both which communicate the same disease at every period after the eruption. It is most probable also, that, in every infectious fever, the morbid matter, after assimilating some of the fluids of the patient affected, passes of in the same state that it was received. Acrimony in the blood is in no case rendered mild by any process in our constitutions: on the contrary, it is always expelled unaltered by some of the emunctories. Pus is never formed of a kindly nature whilst the heat of the body much exceeds the degree that is proper to health.

The theory of concoction, however, which has prevailed since the days of Hippocrates, has been of the most fatal consequence to the science of medicine, and to patients affected with fevers. It precluded all observation of the effects of medicines in the early stages of such fevers, and left the patient to the ravages of their cause. When the idea was added, that heat was the instrument by which the change was effected, the miseries of the sufferers were greatly augmented. The curtains were drawn; the windows shut; the fires large and incessant; and the medicines of the most stimulating kind. It was truly said, that those who recovered escaped through the fire.

Sydenham supposed that the concoction of the febrile matter meant no mo rethan a preparation and separation of the morbific from the sound particles. See Kirkland on Fevers, p. 14, 27.