OP 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 diiferent 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 to feed the fountains : a 

 muscular constriction of a very peculiar kind in the back 

 part of the cavity, for the guidmg 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 larnyx, and without number in the 

 tongue, for the purpose of modulating that air in its passage, 



herbivorous animals the papillae are sharp pointed and directed back- 

 wards to assist in laying hold of the grass. In the cat kind there is 

 a horny or" prickly set covering the tongue, rendering it rough, and 

 enabling it to take firmer hold of the prey. Birds also have a similar 

 contrivance. In fish the tongue is covered by a number of teeth, serv- 

 ing 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 an- 

 imals 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 vege- 

 table aliments, or both, i. e. keeps a mean between graminivorous and 

 carnivorous animals, in the structure and complication of his digestive 

 apparatus, 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. 



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