128 



METHODS FOR THE ANALYSIS OF BLOOD 



i mm. bore 



Position 1 . 



It is necessary, of 



course, that both stop 

 cocks should be properly 

 greased and air tight, 

 and it is also essential 

 that they (especially /) 

 shall be held in place so 

 that they cannot be 

 forced out by pressure 

 of the mercury. Rubber 

 bands may be used for 

 this purpose but it is 

 suggested that elastic 

 cords of fine wire spirals, 

 applied in the same 

 manner as rubber bands, 

 are stronger and more 

 durable. 



After a determina- 

 tion has been finished, 

 the leveling bulb is 

 lowered without opening 

 the upper cock, and most 

 of the mercury is with- 

 drawn from the pipette 

 through c. The water 

 solution from d is read- 

 mitted and the leveling 

 bulb being raised to po- 

 sition 1,' the water solu- 

 tion, together with a 

 supporting little mercury, is forced 

 out of the apparatus 

 through a. (It is well 

 to have a ' funnel drain- 

 ing into a special vessel 

 to catch the water resi- 

 dues and mercury over- 

 flow from a. A consid- 

 FIG. 9. Van Slyke Carbon Dioxide Apparatus, erable amount of mer- 

 (Jour. Biol. Chem., 1917, 30, 289; 1917, 30, 

 347.) (Hawk.) 



Position 3 

 is eo cm below 

 position Z 



