204 ANATOMY OF THE HEAD. 



from the root of the ear to the throat. It is distinctly 

 lobular, its lobes being connected by cellular membrane ; 

 and from each of its lobes ramifies an infinity of minute 

 tubes, which finally unite into one common trunk, and 

 thus empty the secretion of the gland into the mouth. 

 The parotid duct thus finally formed quits the gland, 

 passing along the inner surface of the jaw ; crosses the bone, 

 in company with the submaxillary artery, and pierces the 

 side of the mouth, near to the third molar tooth ; forming 

 a bulbous rising at its termination. 



The submaxillary^ though much smaller than the parotid, 

 are still considerable glands, occupying the lower part of the 

 spac^, termed the channel; a great portion of them being 

 under the parotid gland. The ducts penetrate the buccal 

 membrane, a little anterior to the lingual frenum, by orifices 

 proper to each, which project up in nipple-like risings. 



The sublingual glands are smaller, but far more numerous, 

 than the submaxillary ; and are placed along the under part 

 of the tongue, where, from their lobular form, they become 

 easily detected. They pour out their secretion by little 

 orifices, which may be traced on each side of the mouth. 

 The labial glands are placed under the common membrane 

 of the mouth, on the inner surface of the lips, and are small 

 secreting bodies. The buccal glands are found on each side 

 of the mouth. Follicidose and mucous glands are distributed 

 over the interior of the mouth, the surface of the tongue, 

 and soft palate. There are also the lymphatic glands common 

 to the head, the principal of which are the maxillary. These 

 are situated in the channel towards the superior part. 



The uses of the salivary secretion appear to be to moisten 

 the food, thereby enabling such as is dry to be more readily 

 swallowed. It has, however, functional properties of other 

 kinds, and contains, without doubt, living principles of 

 action, as well as mechanical : by changing the matters 

 taken into the mouth, it commences the work of diges- 

 tion. At all times it is useful, likewise, by moistening the 

 mouth and fauces, thereby keeping them in a constant state 

 of susceptibility. From some experiments made, it would 

 appear that the quantity of saliva furnished by the parotid 

 ducts alone, during the process of eating, is more than a 

 quart per hour. The saliva is also of use in entangling air 



