SUBLINGUAL SALIVA. 343 



measurements gave for the submaxillary saliva 0*004 per cent., for 

 the parotid 0*03 per cent., of this substance, reckoned as potassium 

 sulphocyanate. It contains ptyalin, as shown by its powerful diastatic 

 action on starch. 



The submaxillary saliva in the dog contains much more mucin than in 

 man, and is in consequence much more viscid. It is alkaline in reaction, 100 

 grins, requiring for neutralisation 0*135 to 0'144 grms. of sulphuric acid, 

 reckoned as S0 3 . On standing in contact with air, calcium carbonate is 

 thrown down as a flocculent precipitate, which was previously held in solution 

 by the dissolved carbon-dioxide as bicarbonate. The same result is brought 

 about more rapidly by heating. It contains, at most, only traces of proteid 

 or of sulphocyanate. Its specific gravity is 1*0026 to 1*004. 



The quantitative composition of the saliva obtained on stimulation of 

 the submaxillary gland varies according to the nerve stimulated. The 

 saliva obtained on stimulation of the sympathetic (sympathetic saliva) 

 is scanty in quantity, and contains much mucin, which gives it a viscid 

 consistency. Chorda saliva, on the other hand, is plentiful in quantity, 

 contains less mucin, and is hence a thin watery fluid. The chorda saliva 

 has a specific gravity of 1*0049 to 1*0056, and contains 1*2 to 1-4 per 

 cent, of total solids; sympathetic saliva has a specific gravity of 1/0075 

 to 1-018, and contains 1*6 to 2*8 per cent, of total solids. 1 



Parotid saliva. Human parotid saliva may be obtained by intro- 

 ducing a fine cannnla into Stenson's duct. 2 



It is a thin, mobile fluid, usually clear, sometimes somewhat turbid, 

 and contains no formed element save epithelial cells. It is alkaline in 

 reaction, but the first few drops secreted may be neutral or acid, 

 especially in a state of hunger ; in all cases the alkalinity is less than 

 that of submaxillary saliva. 3 Its specific gravity seems to be very 

 variable (Mitscherlich, 1*006 to 1*008 ; Oehl, 1*010 to 1*012 with scanty 

 secretion, 1*0035 to 1*0039 with plentiful secretion; Hoppe-Seyler, 

 1*0061 to 1*0088); the amount of total solids lies between 5 and 16 

 parts per thousand. It contains traces of proteids, but is free from 

 mucin ; it also contains ptyalin and sulphocyanate. 



The parotid saliva of some animals, such as the dog and horse, is very 

 rich in calcium bicarbonate, and often deposits crystals of calcium 

 carbonate on standing. 4 Stimulation of Jacobson's nerve in the dog 

 produces a flow of saliva from the parotid, poor in organic constituents. 

 If, before this is done, the cervical sympathetic be stimulated, which 

 alone produces no effect, on now stimulating the nerve of Jacobson 

 a flow of saliva is obtained which is much richer in organic con- 

 stituents. 5 



Sublingual saliva. Oehl attempted to obtain human sublingual 

 saliva by a similar method to that described in the case of the other two 

 glands ; he was only able to obtain a very small quantity, insufficient for 



1 Eckhard, JBeitr. z. Anat. u. Physiol. (Eckhard), Giessen, 1860, Bd. ii. For further 

 details regarding the influence of nerves on the composition of saliva, see article on 

 " Mechanism of Salivary Secretion." 



2 Eckhard, loc. cit.; Oehl, Jahresb. u. d. Fortschr. d. ges. Med., Erlangen, 1865, Bd. i. 

 S. 120. See also Brim ton in Sanderson's "Handbook of the Physiol. Laboratory," p. 467. 



3 See Astaschewsky, Jahresb. u. d. Fortschr. d. Thier-Chem., Wiesbaden, 1878, Bd. viii. 

 S. 234 ; Fubini, ibid. , S. 235. 



4 Lehmann, "Physiol. Chem.," Bd. ii. S. 13. 



5 Heidenhain, Arch. f. d. ges. Physiol., Bonn, 1878, Bd. xvii. S. 28 ; also in Hermann's 

 "Handbucb," Bd. v. (1), S. 55. 



