20 SALIVA. 



Sulphocyanide of potassium never occurs in the saliva except in 

 very small quantity. 



Jacubowitseh found O006 of this salt in his own saliva ; and 

 in analysing my saliva I found it to vary between 0'0046 and 

 0*0089 ; according to Wright it ranges in human saliva from 0*5 1 

 to 0'98, which is obviously far too high. 



Although we have already spoken (in the first volume) of the 

 existence of sulphocyanide of potassium in the saliva, yet the very 

 dogmatical assertions of Strahl,* who denies that the presence of 

 sulphocyanogen can be demonstrated, and applies to the experi- 

 ments of his predecessors, such terms as "deficient, irregular, 

 and ill-judged," (notwithstanding that Gmelin has exhibited pure 

 sulphocyanogen in very large quantity from the saliva by distilla- 

 tion,) compel us to refer to the admirable memoirs of Jacubowitseh 

 and Tilanus,t who have demonstrated beyond all doubt the 

 presence of sulphocyanogen by the simplest and most unques- 

 tionable chemical experiments ; Frerichs J has also established the 

 proof of the existence of sulphocyanide of potassium in the saliva. 

 Moreover, it was formerly shown by Marchand. and it has been 

 more recently demonstrated by Wohler and Frerichs, || by direct 

 experiments, that sulphocyanide of potassium does not possess any 

 poisonous properties. 



Local stimulation of the salivary glands, the internal use of 

 prussic acid and the salts of cyanogen, and especially of sulphur, 

 increase, according to Wright, the quality of sulphocyanogen in 

 the saliva. 



In mixed or ordinary saliva the ptyalin is mixed with mucus, 

 so that its properties do not appear to be altogether identical with 

 those which we have described, and its accurate quantitative deter- 

 mination is impossible, independently of the considerable amount 

 of salts contained in the aqueous extract. The aqueous extract, 

 consisting chiefly of ptyalin, was found by Berzelius to amount to 

 40'8-g- of the solid residue of the saliva, while Gmelin fixed it at 

 20'0, and Van Setten^f at 15'62. 



The determinations of the organic matter soluble in water and 

 in alcohol, are very uncertain ; indeed, little or nothing is known 

 regarding this substance. 



* Med. Zeitg. v. d. Ver.f. Preussen, 1847. Nr. 21 u. 22. 



t De Saliva et Muco ; dissert, inaug. Amstelod. 1849. 



Op. cit. p. 764. 



Lehrb. d. Phys. Ch. 1844, S. 410. 



II Ann. d. Ch. u. Pharm. Bd. 65, S. 344. 



IT Op. cit. p. 24. 



