1/2 DIGESTION 



the submaxillary saliva, but it differs in the fact that it does not gelati- 

 nize on cooling. It is so glutinous that it adheres strongly to any 

 vessel and flows with difficulty from a tube introduced into the duct. 

 Like the secretion from the other salivary glands, its reaction is dis- 

 tinctly alkaline. Its organic matter is not coagulable by heat, acids or 

 the metallic salts. 



Secretions from the Smaller Glands of the Month, Tongue and 

 Pharynx. Beneath the mucous membrane of the inner surface of the 

 lips, are small, rounded, glandular bodies, opening into the buccal 

 cavity, called the labial glands ; and in the submucous tissue of the 

 cheeks, are similar bodies, called the buccal glands. The latter are 

 somewhat smaller than the labial glands. Two or three of the buccal 

 glands are of considerable size and have ducts opening opposite the 

 last molar tooth. These are sometimes distinguished as the molar 

 glands. There are also a few small glands in the mucous membrane 

 of the posterior half of the hard palate ; but the glands on the under 

 surface of the soft palate are larger and form a continuous layer. The 

 glands of the tongue are situated beneath the mucous membrane, mainly 

 on the posterior third of the dorsum ; but a few are found at the edges 

 and the tip, and there is a gland of considerable size on either side of 

 the frenum near the tip. All these are small racemose glands, similar 

 in structure to the true salivary glands. In addition to these structures, 

 the mucous membrane of the tongue is provided with simple and com- 

 pound follicular glands, which extend over its entire surface, but are 

 most abundant at the posterior portion, behind the circumvallate 

 papillae. 



In the pharynx and the posterior portion of the buccal cavity, are 

 the pharyngeal glands and the tonsils. In the pharynx, particularly 

 the upper portion, racemose glands, like those found in the mouth, 

 exist in large number. The mucous membrane is provided, also, with 

 simple and compound mucous follicles. The tonsils, situated on either 

 side of the fauces between the pillars of the soft palate, consist of an 

 aggregation of compound follicular glands. The number of glands 

 entering into the composition of each tonsil is ten to twenty. The 

 secretion from these glands and follicles can not be obtained, in the 

 human subject, unmixed with the products of the true salivary glands. 

 It has been collected in small quantity, however, from the inferior 

 animals, after ligature of all the salivary ducts. This secretion is 

 simply a grayish viscid mucus, containing a number of leucocytes and 

 desquamated epithelial scales. It is this which gives the turbid and 

 opaline character to the mixed saliva, as the secretions of the salivary 

 glands are all clear. The products of these glands in the mouth are 



