96 PHYSIOLOGY CHAP. 



of free H -f and OH - ions remaining in the fluid, but, further, the quantity 

 of H -f and OH set free in consequence of the modifications of chemical 

 equilibrium between non -dissociated and associated molecules, are determined. 

 The titratioii methods most commonly employed to estimate the alkalinity 

 of the blood are as follows : 



1. Zuntz neutralised the alkalinity of the blood by a titrated solution of 

 phosphoric acid, 1 c.c. of which corresponds to 0*005 grin, of sodium carbonate. 

 Litmus-paper is used as the indicator. Lassar, on the other hand, employs a 

 decinormal solution of tartaric acid (7 -5 grins, of acid per litre). 



2. Landois adopts the decinormal solution of tartaric acid, and a perfectly 

 neutral, saturated solution of sodium sulphate. As indicator he uses the 

 finest litmus-paper. With these two solutions ten mixtures are made in the 

 following proportions : 



I. 10 parts TQ tartaric acid to 100 parts saturated sol. NaS0 4 . 



II. 20 90 



X. 100 10 



The first mixture is then aspirated to a distance of 8 mm. along a 

 graduated pipette made of a glass tube 1 mm. in diameter, and the blood to a 

 distance of 16 mm., i.e. 8 mm. of each fluid. This mixture is emptied into 

 a watch-glass and the reaction tested. Each successive mixture is employed 

 in the same way until the alkaline solution becomes acid. The degree of 

 alkalinity corresponding to the several mixtures is as follows : 



I. = 0-036 per cent NaOH. VI. = 0-216 per cent NaOH. 



II. -0-072 VII. -0-252 



III. = 0-108 VIII. = 0-288 



IV. = 0-144 IX. =0-324 

 V.= 0-180 X. = 0-360 



Jaksch has modified Landois' method in practice as follows. He too 

 employs a solution of ^ tartaric acid and a concentrated solution of sodium 

 sulphate. He dilutes the first solution 10 and 100 times, making solutions of 

 and ,-TT-^ tartaric acid respectively. These solutions are mixed with the 



solution of sodium sulphate in eighteen mixtures, which contain : 



I. 0-9 c.c. ^Q-0 acid with 0-1 c.c. of NaSO 4 . 



II. 0-8 0-2 



IX. 0-1 0-9 



X. 0-9^.^ 0-1 

 XL 0-8 0-2 



O'l c.c. of blood is dropped into each watch-glass, stirred up, and the reaction 

 tested with litmus-paper. The solutions correspond to the following degree 

 of alkalinity of the blood : 



I. 0-360 NaOH in 100 grms. of blood. 

 II. 0-320 



III. 0-250 

 IX. 0-040 

 X. 0-036 



XVIII. 0-004 



The actual reaction of the blood is measured by the Electrometric Method 

 (concentration cell). Particulars will be found in any modern text-book of 

 physics. 



