18 CONSTITUENTS OF MIXED SALIVA. [BOOK II. 



with that of diastase. This ferment has frequently been termed 

 Ptyalin, though this name was originally applied by Berzelius 1 to the 

 organic matters of the saliva generally, obtained by a method which 

 robbed them of all ferment action, which besides was unknown to the 

 Swedish observer. It is more usual to designate it the Diastatic 

 Ferment (or Enzyme) of the Saliva, or Salivary Diastase. It will be 

 separately discussed in one of the succeeding sections. 



n , By V. Wittich's method, Hiifner 2 obtained from the 



and Munk's salivary glands of the pig a glycerin extract which, in 

 discovery of a addition to very slight diastatic, possessed feeble but 

 proteoiytic decided, proteolytic activity. This ferment was said 

 ferment in to j^ active in alkaline as well as in acid solutions. 

 Munk 3 obtained a similar ferment from mixed saliva, 

 but found that it was very active in acid solutions. 



It is probable that the ferment discovered by both Hiifner and 

 Munk was pepsin, of which minute traces probably make their way 

 into the several fluids of the body. The urine, for instance, is known 

 to contain a trace of diastatic ferment and especially of pepsin, and 

 occasionally, it is said, of trypsin, and of rennet ferment 4 . 



Extractive In disease, certain extractive matters, such as urea, 



matters of leucine and lactic acid, have been discovered in the 

 saliva. saliva. The first of these is probably a normal con- 



stituent, though only present in minute traces. We do not yet know 

 what other extractives occur as regular constituents in health. 



The Saline Constituents of Saliva. 



The Saline Constituents of the Saliva are composed chiefly of 

 alkaline chlorides ; they include, however, also alkaline and earthy 

 phosphates, and, in some cases, earthy carbonates. They are distin- 

 guished by the presence of a salt whose formation appears character- 

 istic of the salivary glands, viz., a soluble sulphocyanate. 



Discovery Treviranus 6 was the first to observe that when a 



of a suipho- solution of ferric chloride is added to saliva it produces 

 a re ddish colour, which was subsequently conclusively 

 shewn by Tiedemann and Gmelin 6 to be due to the 

 presence of sulphocyanic acid in saliva. 



1 Berzelius, Traite de Chimie. Nouvelle edition par Valerius (1839), Vol. in. 

 p. 591. 



2 Hiifner, ' Untersuchungen iiber die ungeformten Fermente.' Journ. f. prakt. 

 Chemie, New Ser. Vol. 5, p. 372. 



3 Munk, 'Untersuchungen liber die ungeformten Fermente im Thierkorper. ' In 

 Maly's Jahresbericht, Vol. 6, p. 270. 



4 W. Sahli, 'Ueber das Vorkommen von Pepsin und Trypsin im normalen mensch- 

 lichen Harn,' Pfliiger's Archiv, Vol. 36 (1885), p. 209. A. Stadelmann, ' Ueber 

 Fermente im normalen Harn,' Zeitschrift f. Biologic, Vol. 24 (1888), p. 226; also 

 ' Untersuchungen iiber den Pepsin-Ferment-gehalt des normalen und pathologischen 

 Harnes.' Zeitschrift f. Biologic, Vol. 25 (1889), p. 215. 



5 Treviranus, Biologie, 1814, Vol. iv. p. 330. 



6 F. Tiedemann und L. Gmelin, Die Verdauung nach Versuchen. Heidelberg u. 

 Leipzig, 1826, Vol. i. p. 8, et seq. 



