4 THE SECRETIONS: 



when dissolved in water, will still indicate an acid reaction, 

 because lactic acid differs from acetic acid in not being vola- 

 tilized at the ordinary temperature used for evaporating animal 

 fluids. In order to determine the amount of free soda in the 

 saliva, the dried residue must be extracted with alcohol ; the 

 free soda (which is left in the residue) must be saturated with 

 acetic acid, the resulting acetate of soda extracted with alcohol,, 

 evaporated, and, by incineration, reduced to carbonate of soda. 

 An analysis of my own saliva yielded the following results. 

 It contained, in 1000 parts : 



Analysis 58. 



Water .... 991-225 



Solid constituents . . . 8-775 



Fat containing cholesterin . . -525 



Ptyalin with extractive matter . . 4*375 



Extractive matter and salts . . 2-450 



Albumen, mucus, and cells . 1-400 



Berzelius 1 found, in 1000 parts of human saliva : 



Water .... 992'9 



Ptyalin . . . .2-9 



Mucus . . . .1-4 



Extract of flesh with alkaline lactates . '9 



Chloride of sodium . .1-7 



Soda . . -2 



According to the analyses of Tiedemann and Gmelin, 1000 

 parts of human saliva contain from 9 to 11*4, or even 11*9 of 

 solid constituents, consisting in 100 parts, of phosphorized fat, 

 extract of flesh, chloride of potassium, lactate of potash, and 

 sulphocyanide of potassium, 31 '25 ; animal matter with traces 

 of alkaline sulphates and chlorides, 1-25 ; ptyalin, with alkaline 

 phosphates, chloride of sodium, and traces of alkaline sulphates, 

 20-00 ; mucus and a little albumen, with alkaline phosphates 

 and carbonates, 40-00. This solid residue yielded on incine- 

 ration 21-95 of inorganic constituents, 17*8 of which were 

 soluble, and 4-1 insoluble in water. Mitscherlich found that 

 1000 parts of human saliva yielded from 14-7 to 16-3 of solid 

 residue, of which 34 were insoluble both in water and in alcohol, 

 42g soluble in water but not in alcohol of -800, and 24 soluble 

 in water and in alcohol. These proportions varied, however, 

 in different analyses. 



1 Thierchemie, p. 219. 



