1835.] Human Saliva. 379 



determined by the addition of sulphuric acid. 29*797 grms. 

 (458*8 gr.) of saliva of the specific gravity 1*0070 required 

 for complete neutralization, 0*0925 grm. (*416gr.) sulphuric 

 acid of the sp. gr. 1*816=0*066 grm. (1*016 gr.) common 

 sulphuric acid. Hence, 100 parts of saliva take 0*223 grm. 

 (3.43 gr.) sulphuric acid for saturation, which neutralize 

 0*174 grm. (2*67 gr.) soda. 



In a second trial 59*594 grms. (917*6 gr.) saliva of sp. gr. 

 1*0074 required 0*163 (2*5 grs.) sulphuric acid of sp. gr. 

 1-816=0*117 grm. (1*8 gr.) sulphuric acid, or in 190 parts 

 0*196 sulphuric acid which saturate 0*153 soda. 



When the sulphuric acid is added, a white flocky preci- 

 pitate falls down, which possesses the properties of the 

 salivary mucus. The first drop of acid produces a muddi- 

 ness, which *as the point of saturation approaches is in- 

 creased. Hence, it is probable, that as no carbonic acid 

 appears to be extricated, the soda exists in combination 

 with the mucus. This idea seems also to be confirmed by 

 the circumstance, that when the saliva is exposed to the 

 air, carbonic acid is absorbed by the alkali and the mucus 

 is precipitated. 



The free alkali is not volatile, for no ammonia was driven 

 off by heating. To determine the quantity of inorganic bases, 

 47*7997 grms. (768*4 grs.) of saliva of the sp.gr., 1*0075 

 were treated with nitric acid till all the organic constituents 

 were destroyed. The dry residue amounted to 0*338 grm. 

 (5*2 grs.) which when dissolved in water, left 0*015 grm. 

 (£ gr.) Muriatic acid dissolved 0*008 grm. (*123 gr.) of 

 this, which after solution yielded a precipitate with ammo- 

 nia, consisting of phosphate of lime, equivalent to 0*0168 

 per cent. The portion which was insoluble in muriatic 

 acid was examined by the blow-pipe and found to be silica. 

 That part which dissolved in water amounting to 0*323 

 grm. (4*97 grs.) was treated with alcohol and chloride of 

 platinum, and precipitated 0*096 grm. (1*47 gr.) of potash 

 =0*209 per cent. 



The solution filtered from this precipitate was evaporated; 

 the residue heated to redness and re-dissolved in water. 

 From which 0*17 grm. (2*6 grs.) chloride of sodium was 

 obtained =0*188 per cent. soda. 



To determine the quantity of chlorine, 22*224 grms. 



