388 M E M O I R S 0/ ^fc^ 
which open into the mouth very near to one another, and the 
Gkndidce Alctsillares internee Bind Sub-Unguales ^o below lupply 
the fame kind of juices by orifices, that open fo near to each 
other, as to iecare the mixture of the two different juices: 
The Dr. afferts, that thefe different forts of liquors, fepa« 
rated by thele glands, are of fuch a nature as to be apt to fer- 
ment upon their firll mixture, but perhaps more confiderably, 
when they come to be digefted by the heat of the itomach^ to 
that the collu6tation or fermentation, which attenuates and 
conccfls the food in the ftomach, does not ordinarily arife be- 
tween the aliment, and Saliva^ but between the feveral parts 
of the Saliva itfclf 5 and indeed if the Saliva did not confift 
of two juices, whofe nature is in fuch a manner different, as 
to render them apt to ferment upon their mixture, it would be 
very hard to conceive, how it ihould lerve fo readily and indif- 
ferently for the digeftion of all eatables, not only of a different, 
but of a contrary nature 5 how it fliould ferment with acids as 
well as Akalles , digeft things that are cold as well as hot or 
temperate, ^c. the concofiion of all which is rationally ac- 
counted for, by fuppofing that the fermentation, which ferves 
for the digeflion of the food, arifes from a peculiar difference 
in the nature of two juices, which conilitute th^ Saliva: And 
this feems to be as effeffual, and a more certain way to atte- 
nuate and diffolve the groffer parts of our food, than if the 
fermentation was made only between the Saliva and the ali- 
ment 5 befides, the Saliva^ upon the mixture of its condituent 
juices, feems to dilcover a fermentation, even at thofe times, 
when we do not a6:ually eat 5 for it is always attended with 
bubbles and a froth, when it has not been at all agitated in the 
mouth, and many of thofe bubbles will remain for fome con- 
(iderable time after we have fpit it out. 
Nature therefore, having appointed the Saliva for the digef- 
tion of the food, has taken care that it fhall be thrown in upon 
the aliment on every fide 3 thus, the Glandulee Nuckiantfy and 
the ^arotideSy fupply with their juices that part of the food 
which lies on the outfide of the gums, between the cheeks and 
the teeth, and the Glandiil^e 3Iaslllares internee ^^ fub-linguales 
beflow their liquor upon the meat which is within the teeth 
and gums : Nature has alfo had a regard to the mixture of the 
two different juices of the Saliva^ which is neceffary to its 
fermentation as is abovementioned, by placing the orifices of 
the falival glands near each other: The Saliva^ being thus 
mixed, does, partly as it is agitated with the food by the teeth, 
and 
