106 



METHODS FOR THE ANALYSIS OF BLOOD 



out the last portions of air, is also let out at c. D is now connected 

 with the motor and shaken till all but 20 c.c. of the solution have 

 been displaced by nitric oxide and driven back into A. A mark 

 on D indicates the 20 c.c. point. One then closes a and turns c and 

 / so that D and F are connected. The above manipulations require 

 between one and two minutes. 



2. Decomposition of the Amino Substance. Of the amino 

 solution to be analyzed 10 c.c. or less, as the case may be, are 



measured off in B. Any excess 

 added above the mark can be 

 run off through the outflow tube. 

 The desired amount is then run 

 into D, which is already connect- 

 ed with the motor, as shown in 

 Fig. 2. It is shaken when a-amino 

 acids are being analyzed for a 

 period of three to five minutes. 

 With a-amino acids, proteins, or 

 partially or completely hydro- 

 lyzed proteins, we find that at 

 the most five minutes' vigorous 

 shaking completes the reaction. 

 Only in the case of some native 

 proteins which, when deaminized 

 form unwieldy coagula that 

 mechanically interfere with the 

 thorough agitation of the mixture, 

 a longer time may be required. In 

 case a viscous solution is being 

 FIG. 3. Section of Van Slyke Ap- analyzed and the liquid threatens 

 paratus. (Hawk.) to foam QVer into p B j g rinsed 



out and a little caprylic alcohol is 



added through it. For amino substances such as amino purins, 

 requiring a longer time than five minutes to react, one merely 

 mixes the reacting solutions and lets them stand the required 

 length of time, then shakes about two minutes to drive the nitrogen 

 completely out of solution. 



When it is known that the solution to be analyzed is likely to 

 foam violently, it is advisable to add caprylic alcohol through B 

 before the amino solution. B is then rinsed with alcohol and dried 



