serves for the Digestion of the Food, arises from a peculiar difference in the Nature of two Juices, which constitute the Saliva, it will be easie to give a rational Account of our Concoction of innumerable things of a different Nature. And this seems to be as effectual, and a more certain way to attenuate and dissolve the grosser Parts of our Food, than if the Fermentation were made only between the Saliva and the Aliment: Besides, the Saliva seems to discover a Fermentation upon the mixture of its constituent Juices, even at those times when we do not actually eat; for it is always attended with Bubbles, and a Froth, when it has not been at all agitated in the Mouth, and many of those Bubbles will remain for some considerable time after we have spit it out.
Nature therefore having appointed the Saliva for the digestion of the Food, has taken care that it shall be thrown in upon the Aliment on every side. Thus the Glandulæ Nuckianæ , and the Parotides , supply their Juices to that part of the Food, which lies on the outside of the Gums, between the Cheeks and the Teeth, and the Glandulæ Maxillares internæ , and Sublinguales , do bestow their Liquor upon the Meat, which is within the Teeth and Gums. Neither has she had a Regard only to that Supply, which is due to all the parts of our Food, but likewise to the mixture of the two different Juices of the Saliva , which is necessary to its Fermentation. And therefore, as I have already observ'd, the Orifices of the Ducts, which belong to one sort of Glands, are placed near the Aperture of a Duct, which conveys a Juice from one of the other Glands. So the Ducts of the Glandulæ Nuckianæ , and the Ductus Stenoniani , do on each side open into the Mouth, near one another; and the salivatory Ducts of the Glandulæ Sublinguales , and the Maxillares internæ , though they have