292 THE MIXED SALIVA IN THE MOUTH. 



Mucin is absent, hence the parotid saliva is fluid, is not sticky, 

 and can readily be poured from one vessel into another. It contains 

 1*5-1 '6 per cent, of solids (Mitscherlich, van Setten) in man, of which 

 0'3-1 P per cent, is inorganic. 



Amongst the organic substances the most important are Ptyalin, a small 

 amount of urea (Gobley), and traces of a volatile acid (Caproic ?) 



Of the inorganic constituents the most abundant are potassium and sodium 

 chlorides ; then potassium, sodium, and calcium carbonates, some phosphates 

 and a trace of an alkaline sulphate. 



(b.) The Sub -maxillary Saliva is obtained by placing a cannula in 

 Wharton's duct; it is alkaline, and may be strongly so. When allowed 

 to stand for a long time, fine crystals of calcium carbonate are deposited, 

 together with an amorphous albuminous body. It always contains 

 mucin (which is precipitated by acetic acid) ; hence, it is usually some- 

 what tenacious. Farther, it contains ptyalin, but in less amount than in 

 parotid saliva ; and, according to Oehl, only 0'0036 per cent, of potassium 

 sulphocyauide. 



Chemical Composition. Sub-maxillary saliva (dog) : 

 Water, .... 991-45 per 1,000, 

 Organic Matter, . . 2 -89 ,, ,, 



( 4-50 NaCl and CaCl 2 . 

 Inorganic Matter, . . 5 - 6G< 1'IG CaCO 3 , Calcium and Magnesium 



( phosphates. 



Pfluger found that 100 cubic centimetres of the saliva contained 0'6 O 64'7 C0 2 

 (part could be pumped out, and part required the addition of phosphoric acid); 

 0-8 N.; or, in 100 vol. gas, 0.91 O ; 97 '88 C0 2 , 1'21 N. 



(c.) The Sub-lingual Saliva is obtained by placing a very fine cannula 

 in the ductus Rivinianus (Oehl), is strongly alkaline in reaction, very 

 sticky and cohesive, contains much mucin, numerous salivary corpuscles, 

 and some potassium sulphocyanide (Louget). 



147, The Mixed Saliva in the Mouth. 



The fluid in the mouth is a mixture of the secretions from the 

 salivary glands, and the secretions of the mucous glands of the mouth. 



(1.) Physical Characters. The mixed saliva of the mouth is a some- 

 what opalescent, tasteless, odourless, slightly glairy, fluid, with a specific 

 gravity of 1,004-1,009, and an alkaline reaction. The amount secreted 

 in 2-i hours 200 to 1,500 grammes (7-70 oz.) ; according to Bidder 

 and Schmidt, however, 1,000 to 2,000 grammes. The solid con- 

 stituents = 5'8 per 1,000. 



Composition. The solids are: Epithelium and mucus, 2'2 ; ptyalin and 

 albumin, 1/4 ; salts, 2'2 ; potassium sulphocyanide, 0'04per 1,000. The ash con- 

 tains chiefly potash, phosphoric acid, and chlorine (Hammerbacher). 



Decomposition products of epithelium, salivary corpuscles, or the remains of food, 



