96 THE CHEMICAL CONSTITUTION OF THE PROTEINS 



less than -oq|| c.c. The burette is of 3 c.c. capacity, and is graduated 

 into O'l c.c. divisions about I mm. apart, so that by estimating tenths 

 of a division gas volumes can be read to -ooi c.c. The burette must 

 be carefully calibrated. I c.c. of amino solution is required for 

 analysis. 



The removal of air from the apparatus is more easily effected as 

 follows : 



The apparatus is shaken once until sufficient nitric oxide is formed 

 to force the liquid in the chamber down to the mark at which the re- 

 agent stands for introducing the amino solution. The tap a is closed 

 and tap c is turned so that the gases can escape at c. The vessel is 

 then shaken rapidly for two minutes with the motor. The air is more 

 completely removed by this procedure than by the other procedure. 

 The deaminising bulb is then connected through c with the gas 

 burette. 



Soft heavy-walled rubber tubing must be used for the connections. 

 "Stethoscope" tubing with a wall 3 or 4 mm. thick is very suitable. 



