114 



METHODS FOR THE ANALYSIS OF BLOOD 



should give a deep rose-red color with phenolphthalein. If only 

 a faint pink color is obtained, the salt is not sufficiently pure. 



The solutions are mixed in the proportions indicated below 

 to obtain the desired PH> 



TABLE FOR PREPARATION OF STANDARD COLORS 



THE HALDANE GAS-ANALYSIS APPARATUS l 



Principle. The Haldane method of analysis of expired air is 

 simple and easily learned. The apparatus (Fig. 4) consists of a 

 gas burette, a control burette of the same size (both surrounded 

 with a water jacket),, and bulbs containing dilute caustic potash 

 or soda solution for the absorption of the carbon dioxide and an 

 alkaline pyrogallate solution for the absorption of the oxygen. 

 The gas burette is connected with the bulbs by a two-way stop- 

 cock, which allows a sample of gas to pass into either bulb. A 

 control tube (10) is put into connection with the burette through 

 a manometer tube, which is connected with the alkali bulb, and 

 can be made to compensate for any changes in temperature that 

 may occur during the course of the analysis. For an analysis the 

 gas is transferred to the burette from the sampling tube, saturated 

 with water vapor over mercury, and then measured, after which 



1 Macleod: Physiology and Biochemistry in Modern Medicine, 2d 

 Edition, p. 559. 



