HALDANE GAS-ANALYSIS APPARATUS. 71 



LABORATORY FORM. 



The laboratory form of the Haldane gas-analysis apparatus has been 

 used considerably for analyses of atmospheric and expired air in con- 

 nection with the respiration experiments conducted in this research. 

 A detailed description of the apparatus, its method of use, and some of 

 the modifications in technique made in this laboratory will therefore be 

 given. Descriptions of this apparatus have previously been published 

 by Haldane. 1 



The general principle of the apparatus is as follows: The gas to be 

 analyzed is taken into a burette surrounded by a water-jacket, and is 

 there saturated with water-vapor over mercury and measured. In 

 the same water-jacket is a control tube, which is of about the same 

 volume as the burette. The measuring burette and the control tube 

 can be put into connection with one another through a manometer 

 containing dilute potash solution. The control tube can be set at 

 atmospheric pressure and compensates for the changes in temperature 

 and pressure. The gas is first freed from carbon dioxide by means of 

 potassium hydroxide, then from oxygen by absorption with potassium 

 pyrogallate, measurements being made before and after each operation. 

 From the differences of the three readings, the volumes of the carbon 

 dioxide and of the oxygen can be calculated. 



Description of Parts. 



The apparatus in detail is shown in figure 32. A measuring burette, 

 A, is placed in a cylindrical water-jacket, B. The total content of the 

 burette is 21 c.c, 15 c.c. of this being included in the bulb at the upper 

 part of the burette. From 15 c.c. to 21 c.c. it is graduated to 0.01 c.c; 

 the total length of the divided portion is 60 cm. ; the bore is 4 mm. At 

 the top of the burette is a stopcock, (7, with two outlets arranged so 

 that air can be drawn through one outlet from the sampler and air can 

 be sent through the other outlet to the absorption pipettes. The lower 

 part of the burette extends through a rubber stopper at the bottom of 

 the water-jacket and is connected to the leveling bulb D by means of 

 rubber tubing. 



The pipette E, for the absorption of carbon dioxide, consists of a 

 cylindrical bulb, 13 cm. in length and 30 mm. in diameter. It can be 

 put in communication with the burette A by means of the two right- 

 angle stopcocks F and G. At the bottom of the potash pipette E is a 

 glass tee H, one branch of which is connected by rubber tubing to the 

 leveling bulb J containing potash. The other branch connects to a 

 three-way stopcock, /, which in turn is connected to a compensation 

 tube, K. The pipette for the absorption of oxygen is shown at L. 

 This is connected to the burette A by means of the two right-angle 

 stopcocks F and G, and is filled with potassium pyrogallate which can 



'Haldane, Journ. Physiol., 1898, 22, p. 465; Methods of air analysis, London, 1912. 



