SALIVA. 387 



expose the substance (No. 4) to the air after such neutralization 

 it absorbs moisture ; the animal matter is dissolved, while the 

 salts remain in crystals. The liquid being poured off is found to 

 contain no sulphuric acid. The animal matter thus separated 

 from the salts has a red colour and an acid reaction. With 

 acids, potash, ammonia, and corrosive sublimate, it gives no pre- 

 cipitate. Acetate of lead throws down a slight precipitate again 

 redissolved by boiling. Perchloride of iron gives a flocky red 

 precipitate not again dissolved by water. Nitrate of silver gives 

 a precipitate soluble in ammonia. 



When sulphuric acid is added to saliva to neutralize the soda 

 which it contains, white flocks precipitate. These flocks consti- 

 tute salivary mucus. As they continue to fall till the soda is sa- 

 turated, and as no effervescence is perceptible, the probability is, 

 that the soda in saliva is in combination with this mucus. The 

 following table exhibits the saline contents of 100 parts of sali- 

 va as determined by Mitcherlich:* 



Chloride of potassium, 



Potash combined with lactic acid, 



Soda combined with lactic acid, 



Soda combined with mucus, 



Phosphate of lime, 



Silica, 



0-494 



Or nearly half-a per cent. 



Berzelius made an analysis of saliva, probably about the year 



1810 ;f though we did not become acquainted with his results in 



this country till about the year 18134 According to him 100 



parts of saliva consist of 



Water, . . . 992-9 



Salivin, .... 2-9 

 Mucus, . . . 1-4 



Alkaline chlorides, . . 1-7 



Lactate of soda with animal matter, 0'9 

 Soda, . . . 0-9 



1000-7 



* Poggendorfs Annalen, xxvii. 337. 



f No such analysis is to be found in the 2d volume of his Djurkemien, pub- 

 lished in 1808. 



f Annals of Philosophy, ii. 380. 



