DISSOCIATION CURVE. 



133 



should be at least 200 c.c.* The narrow tubes are connected with thick-walled 

 (pressure) rubber tubing which should be wired on to the glass tubes. The rubber 

 tubes are closed by screw clips (1 and 2). File marks are made at one of the 

 tapering ends of the tonometer, the distances between them corresponding 

 approximately to one cubic centimeter. 



FIG. 36. Apparatus for the determination of the Dissocia- 

 tion Curve. (In place of M the manometer shown in Fig. 36a 

 should be used) . 



THE BAROMETER consists of a vertical thick-walled glass tube about 1.25 

 metres long and of about 3 mm. bore bent on itself near one end, and with the 

 other end dipping into mercury contained in a wider flat-bottomed (specimen) 

 tube (the mercury reservoir) closed by a perforated cork. The barometer tube 



*It would be preferable to use a tonometer twice as large since this would 

 diminish errors due to the addition of the gas given off from the blood. 



