‘It is to be imagin’d then, that a Fever or Ague is an extraordinary Boyling or Fermentation, excited in the Mass of Blood; that this Fermentation against Nature does alter the Blood, disturbs its motion, and perverts the Oeconomy of the whole Body, that the principle or immediate Cause of that Fermentation, is an evil Leven, which partakes of Acides or Sharpness, which infects and agitates the Humours in divers manners, whence proceeds the difference of Fevers, as well as the Division which may be made of them, into intermittent, continual, accidental or Symptomatick Fevers.
In the intermittent Fevers, the Leven does often arise from a portion of bad Chyle, or from those Aliments which we have taken, of which the first Degree of Corruption, is to contract a fermentative Eagerness, which excites the Fever. Those strange Juices not being capable of joyning with the rest of the Mass of Blood, cause in it a boyling and a disturbance, till they be corrected, or separated from the other Humours.’
François Monginot, A new mystery in physick discovered, by curing of fevers & agues by quinquina or Jesuites powder. Translated from the French, by Dr. Belon, with additions (1681)