428 DIGESTION. 



dioxide all results calculated at C. and 760 mm. pressure. The greater 

 part of the carbon dioxide was chemically combined. 



The two kinds of submaxillary secretion just named have not thus 

 far been separately studied in man. The secretion may be excited by an 

 emotion, by mastication, and by irritating the mucous membrane of the 

 mouth, especially with acid-tasting substances. The submaxillary saliva 

 in man is ordinarily clear, rather thin, a little ropy, and froths easily. 

 Its reaction is alkaline toward litmus. The specific gravity is 1.002- 

 1.003, and it contains 3.6-4.5 p. m. solids. 1 As organic constituents 

 are found mucin, traces of protein and diastatic enzyme, which latter is 

 absent in several species of animals. The inorganic bodies are alkali 

 chlorides, sodium and magnesium phosphates, and bicarbonates of 

 the alkalies and calcium. Potassium sulphocyanide occurs in this 

 saliva. 



The Sublingual Saliva. The secretion of this saliva is also influenced 

 by the cerebral and the sympathetic nervous system. The chorda-saliva, 

 which is secreted only to a small extent, contains numerous salivary 

 corpuscles, but is otherwise transparent and very ropy. Its reaction 

 is alkaline, and it contains, according to HEiDENHAiN, 2 27.5 p. m. solids 

 (in dogs). 



The sublingual secretion in man is clear, mucilaginous, more alka- 

 line than the submaxillary saliva, and contains mucin, diastatic enzyme, 

 and potassium sulphocyanide. 



Buccal mucus can be obtained pure from animals only by the method 

 suggested by BIDDER and SCHMIDT, which consists in tying the exit to 

 all the large salivary glands and cutting off their secretion from the mouth. 

 The quantity of liquid secreted under these circumstances (in dogs) was 

 ;so very small that the investigators named were able to collect only 2 

 grams of buccal mucus in the course of one hour. It is a thick, ropy, 

 sticky liquid containing mucin; it is rich in form-elements, above all in 

 flat epithelium cells, mucous cells, and salivary corpuscles. The quantity 

 of solids in the buccal mucus of the dog is, according to BIDDER and 

 SCHMIDT, 3 9.98 p. m. 



Parotid Saliva. The secretion of this saliva is also partly dependent 

 on the cerebral nervous system (n. glossopharyngeus) and partly on the 

 sympathetic. The secretion may be excited by emotions and by irri- 

 tation of the glandular nerves, either directly (in animals) or reflexly, 

 by mechanical or chemical irritation of the mucous membrane of the 

 mouth. Among the chemical irritants the acids take first place. Mas- 



1 See Maly's " Chemie der Verdauungssafte und der Verdauung," in Hermann's 

 Handb., 5, part II, 18. This article contains also the pertinent literature. 



2 Studien d. physiol. Institute zu Breslau, Heft 4. 



3 Die Verdauungssafte und der Stoffwechsel (Mitau and Leipzig, 1852), p. 5. 



