As the Juices, which constitute the _Saliva_, do ferment upon their mixture, so it is probable, that from their Mixture and Fermentation there results such a _Tertium quid_, as is apt to ferment with the Bile. And therefore, when the Aliment has been under the Fermentation, excited by the _Saliva_, a sufficient time, it is then thrown into the _Duodenum_, where it meets with the bilious Juice, which flows into that Intestine from the Liver, from which a new Fermentation seems to begin; and the Commotion of the Parts of the Aliment being still continued, does carry on the Business of Digestion until the Food is perfectly concocted: Though it is probable, that this new Fermentation serves not only for the more perfect Digestion of the Food, but likewise for the Separation of the Chyle from the feculent Parts. Neither do I by a random Guess, and an ungrounded Conjecture, suppose that from the Mixture and Fermentation of the two Juices, which constitute the _Saliva_, there results a Matter, which is apt to ferment with the Bile. But to me the Notion seem'd to be confirmed by an Experiment that I made. For considering with my self, that the Bile is generally allow'd to have much of a saponary Nature, I made a Solution of Soap in fair Water, and mix'd it with the Oils of Turpentine and Vitriol first put together, and from their Mixture I observ'd a very easie and gentle Fermentation, which continued for a considerable time. _A Discourse concerning some Influence of _Respiration_ on the _Motion_ of the _Heart_, hitherto unobserved. By _J. Drake_, M. D. F. R. S._ Tho' divers accurate Treatises of the _Heart_, and its Action, have been written by Learned Men of several Nations, especially by two of our own Country; the Great Dr. _Harvey_, to whose happy Sagacity this Nation owes the Glory of the Invention of the _Circulation_ of the _Blood_; and the incomparable Dr. _Lower_, to whom we are beholden for a compleat Display of the _Mechanical Structure_ of the _Heart_, and a most ingenious Rationale of its Action. Yet there remain several Doubts and Difficulties about it (in my Opinion) not sufficiently accounted for; towards the resolving some of which, I shall offer what my own Thoughts have suggested to me, and leave it to the Consideration of the Reader. The Learned Dr. _Lower_ (whose accurate Piece on this Argument will insure his Reputation so long as Physical Knowledge shall last in esteem) has so well accounted for the _Systole_, or Contraction of the Heart, from the _Mechanical_ Structure of it, that he seems almost to have exhausted the Subject; and had he been as happy in discovering the true cause of the _Diastole_, he had left little room for the Industry and Sagacity of others about this _Viscus_.