Royal Society. 387 
it more apt and eafy to be divided but feems to be the 
ferment, by which the food is diflolved and digefted, and 
therefore it is intmiately mixed therewith by the teeth's agitat- 
ing them together m maftication ^ this liquor, which we com- 
monly call the Saliva or fpittle, feems to be a compoiition of 
two feveral juices, very different in their natures ; and there- 
fore the feveral parts of it are feparated by their proper glands j 
nature having planted no fewer than four pair about the mouth, 
which fupply the juices that conftitute the Saliva-^ viz. the 
Parotides and the GlanduliC Nuckimide^ the Ghvidulce Afaxil- 
lares imernae and the Sith-linguales j of thefe two juices, 
Dr. Havers takes one of them to be an acid, the other an 
oleaginous liquor, iomething like oil of turpentine: For 
amongft feveral experiments, the following gave the Dr. 
moft (atisfa£tion : He took a piece of raw fldfh, and having cut 
it into pieces, but much larger, than what our more lolid food 
is reduced to by a due mallication, he mixed therewith fome 
crumbs of bread, then he poured upon them oil of turpentine 
and upon that oil of vitriol, and ihaking them together, he 
digefted them for four hours in Salneo Mari^^ and then 'hak- 
ing them again in the glafs, he found the meat dilfolved, and 
all become a thickifh pulp 5 the Dr. could not but take no- 
tice, that oil of camphire, tho' it does not orherwife feem much 
different from oil of turpentine, and oil of vitriol, being 
mixed together produce an effervelcence, as well as oil of tur- 
pentine and oil of vitriol, yet did not touch the meat upon 
which he poured them, fo as in the lead to diffolve them ; the 
Dr. found,"^ that an acid and a folution of fait of tartar dif- 
folved fome part of the fleHh meat, when mixed with it, but 
yet neither fo foon nor fo perfectly, as the two beforementioned 
oils did y and the Dr. the rather conje6lures that one of thofe 
juices, which conftitute the Saliva^ is more of the nature of 
oil of turpentine than of a fixed fait, becaufe it will correal 
and temper even oil of vitriol, fo as to render it more toler- 
able to the fibres of the fl:omach: The Dr. fuppofes, that 
four of the eight falival glands, fupply one of thefe juices, 
and the other four the other^ and this feems to be a very good 
reafon why they are fo difpofed and the orifices of their dudls 
fo ordered, that the juice fupplied by one gland, is difcharged 
into the mouth very near the orifice, by which the juice of a 
different nature is tranimitted from another, fo that they mull: 
neceffarily meet and mix together 5 thus the Glandulie N/fcki- 
^//.-f and the Tamides throw in two different juices by orifices, 
C c c z which 
