ANATOMY 



wnly reduce the food into ft powder, or at 



nil events into a dry mass, that could not 



-llowed withoutgreatdiffici;!t\. To 



tliis inconvenience, it is plentifuJ- 



ly moistened with a watery fluid called 



saliva, and is thereby converted int 



.. iiicli can In com eyed into the 

 stoma'-h u it li perfect facility. The source 

 of this fluid is, in several glandular bodies, 

 situated near the mouth, and sending ex- 

 -, which cenvey the secret- 

 ed fluid into that cavity. As t!:- 

 move, the muscles compress these glands, 

 and squec/e tlie secreted fluid into the 

 mouth. The tongue is constantly cm- 

 ployed in bringing again under the action 

 of the teeth those portions of the food 

 which escape from between theffl ; and 

 the closure of the lips prevents it from 

 falling out of the mouth. 



The true salivary glands are tliree in 

 number, on each side of the head. The 

 ud in the space left between 

 the ear and the lower-jaw-bone ; and is 

 called, from its situation, the parotid. Its 

 duct pierces the middle of the cheek. 

 The two others are placed under the 

 tongue, and are called the submaxilltry 

 and suhlingual. Their ducts join to open 

 ty a common orifice, at the side of the 

 membrane called the frenum of the 

 tongue, which ties the under surface of 

 that organ to the inside of the lower jaw. 

 Hesides these large salivary glands, there 

 are other small granular bodies, which 

 pour a mucous fluid into the mouth ; 

 .re named, according totheir situa- 

 tion, glaudulx labiales, huccales, Sic. 



The cavity oi'the mouth in which the 

 process of mastication goes on is not a 

 very extensive one. There is a small 

 space left between the cheeks and the 

 Ui tli i \u rnally ; but \vithin the teeth the 

 tongue occupies nearly the whole room. 

 The upper boundary is formed by the pa- 

 late or roof of the mouth, and the lower 

 by the surface of" the tongue. The mouth 

 opens behind, by a toll Table free commu- 

 nication, into a membianous bag, called 

 ihe pharynx. The surface of the mouth 

 -y where covered by a soft and 

 smooth membrane. This is of course 

 kept constantly in a moist - 

 glands alMAeenumeratcdcontimially pour 

 moii- or less of their secretion into the 

 ca\ it\ . The membrane of the mouth is 

 continuous with the external surface of 

 the bod\ ; but UK- skin assumes a more 

 delicate organi/ution, as must be appa- 

 rent to e\ ery bod\, from the change of 

 colour at the lips. 



#173- of the pkarytus. The masticated 



aliment is collected on the back of the 

 tongue, which is then carried upwards, 



k wards, to discharge it in- 

 pharynx. This bag : ./.fi- 

 lar fibres I'forming the nut. 

 constrictores pharyngis) which contract, 

 -ively, in order to propel the food 

 towards the stomach. But as there are 

 several organs communicating with the 

 pharynx, the food might pass in a wrong 

 direction, if the parts were not so con- 

 trived as to prevent such occurrences. 

 In the upper and anterior part of the 

 \, the nostrils open by two large 

 and free apertures. Between thi 

 the entrance from the mouth is found a 

 fleshy and moveable curtain, called the 

 soft palate, or velum pendulum palati. 

 There is a small body, of a pointed figure, 

 projecting from the middle of this organ, 

 and known by the name of the uvula. 

 This curtain and the uvula can be easily 

 seen in the throat of a living person. It 

 admits of being elexated so as to shut 

 the opening of the nostrils ; and its ac- 

 tion is exemplified in the act of vomiting: 

 the food is forcibly thrown into the pha- 

 rynx, and would pass mostly into the 

 nose, were it not prevented by the soft 

 palate. From the uvula the membrane is 

 continued on either side, in an arched 

 form, towards the root of the tongue, and 

 it contains a glandular body, called the 

 tonsil, which secretes a mucous fluid, to 

 lubricate the parts, and facilitate the pas- 

 sage of the aliment. The larynx open-: 

 into the pharynx, jiutatthe root of th<- 

 tongue; over tliis part, which is '. 

 the glottis, every morsel of the foe 



yet, so exquisitely ten- 

 der is Uie membrane of the wind pipe, 

 that the contact of the smallest extrane- 

 ous body excites a convulsive pa 

 of coughing, that does not cca-e ur.til the 

 offending matter be removed H< 

 are two objects to be effected ; the func- 

 tion of respiration requires that the 

 pipe should have a free commun 

 with the external air, while the irritable 

 nature of its membrane demands that no 

 extraneous body should find ad 

 points an* 



: -icily mechanic :d contrivance; In 

 ture which prod 



eficct, independently of the will of the 

 animal, and merely in consequence of 

 those motions whirli the organ- , 

 in the office of deglutition. At t'n 

 of the tongue, and just in front of the 

 . is a cartilaginous valve, called the 

 epiglottis. \\ hen the parts are Rt rest, 

 tliis valve stands perpendicular, and cm> 



