504 ORGANS OF DIGESTION. 



mastication, independently of the emission of their fluid being 

 provoked by hunger. Owing to the similitude of their struc- 

 ture, and to their not being regularly supplied like other glands 

 with capsules, their limits are occasionally so inexactly traced, 

 that they continue into each other by adjacent points, and form 

 thus an uninterrupted chain.* 



They all are of the conglomerate kind, or, in other words, con- 

 sist in a congeries of smaller glands or lobes and lobules. They 

 are well furnished with arteries; which are branches, from the 

 external carotid, and go in several trunks instead of in a lead- 

 ing one. The parotid is commonly supplied by trunks coming 

 directly from the external carotid, the submaxillary is supplied 

 from the facial artery, and the sublingual gland from the lin- 

 gual artery. Their nerves come from the fifth pair, and from 

 the portio dura. 



The retrograde injection of their excretory ducts shows how 

 the latter are formed by the assembling of branches from the 

 different lobules. These ducts consist of two coats, a fibrous 

 one externally, and a mucous one internally. 



CHAPTER VI. 



OF THE PHARYNX AND (ESOPHAGUS. 

 SECT. 1. OF THE PHARYNX. 



THE Pharynx (Pharynx) is a large membranous cavity, 

 placed between the cervical vertebrae and the posterior part of 

 the nose and mouth. It extends from the base of the cranium 

 to the lower part of the cricoid cartilage, or to the lower part 

 of the fifth cervical vertebra. It is in contact, behind, with 

 the vertebrae and the muscles lying upon them, being simply 

 attached there by loose cellular substance; above, it adheres 

 to the cuneiform process of the os occipitis, and to the point of 

 the petrous portion of the temporal bones; in front, to the pos- 

 terior part of the upper and of the lower maxilla near the ter- 



* Bichat, Anat Descrip. vol. v. p. 24. 





