OF THE MUSCLES. 
81 
There are brought together within the cavity of the 
mouth more distinct uses, and parts executing more dis¬ 
tinct offices, than I think can be found lying so near to 
one another, or within the same compass, in any other por¬ 
tion of the body: viz. teeth of different shape,* first for 
cutting; secondly for grinding: muscles, most artificially 
disposed for carrying on the compound motion of the low¬ 
er jaw, half lateral and half vertical, by which the mill is 
worked: fountains of saliva, springing up in different parts 
of the cavity for the moistening of the food, whilst the 
mastication is going on: glands,j* to feed the fountains; a 
muscular constriction of a very peculiar kind in the back 
part of the cavity, for the guiding of the prepared aliment 
into its passage towards the stomach, and in many cases 
for carrying it along that passage; for, although we may 
imagine this to be done simply by the weight of the food 
itself, it in truth is not so, even in the upright posture of the 
human neck; and most evidently is not the case with 
quadrupeds, with a horse for instance, in which, when 
pasturing, the food is thrust upward by muscular strength, 
instead of descending of its own accord. 
In the meantime, and within the same cavity, is going 
on another business, altogether different from what is here 
described, that of respiration and speech. In addition 
therefore, to all that has been mentioned, we have a pas¬ 
sage opened, from this cavity to the lungs, for the admis¬ 
sion of air, exclusively of every other substance; we have 
muscles, some in the larynx, and without number in the 
tongue, for the purpose of modulating that air in its passage, 
with a variety, a compass, and precision, of which no other 
musical instrument is capable. And, lastly, which in my 
opinion crowns the whole as a piece of machinery, we have 
a specific contrivance for dividing the pneumatic part from 
take firmer hold of the prey. Birds also have a similar contrivance. In 
fish the tongue is covered by a number of teeth, serving the same purpose. 
Paxton. 
* In each jaw there are four incisores, or cutting teeth, two canine 
which may be ranked with the former, only more pointed; four small 
molar , and six large molar or grinding teeth. And as the teeth of ani¬ 
mals indicate the food on which they are destined to subsist, so from 
analogy we may infer that man is called to use either animal or vegetable 
aliments, or both, i. e. keeps a mean between graminivorous and carniv¬ 
orous animals, in the structure and complication of his digestive appara¬ 
tus, without deserving on that account to be called omnivorous: for it is 
known, that, a great number of the substances upon which animals feed 
are of no use in the support of man.— Paxton. 
t The principal of these are the parotids, see Plate XX. 
