206 METHODS FOR THE ANALYSIS OF BLOOD 



sufficient water to bring the volume to 60 c.c. (27 c.c. of water in 

 all, and 30 c.c. of picric acid may be measured from burettes if 

 a 60 c.c. measuring flask is not available). The contents of the 

 flask are mixed, and after ten minutes are filtered. To 40 c.c. of 

 the filtrate 10 c.c. of the standard silver nitrate solution are added 

 with 2 drops of caprylic alcohol. The solutions are thoroughly 

 mixed, and preferably allowed to stand over night to allow the 

 AgCl to coagulate and settle. The supernatant solution is decanted 

 through a small filter paper and 20 c.c. are titrated in accordance 

 with the method of Van Slyke and Donleavy, see page 202. The 

 calculation is also the same since the 20 c.c. of filtrate titrated in 

 this case, as in the method of Van Slyke and Donleavy, represent 

 0.8 c.c. of the original material, blood or blood plasma. 



Solutions. I. Silver Nitrate Solution. An acid M/29.25 

 solution of silver nitrate, 1 c.c. of which is equivalent to 2 mg. 

 of NaCl. 



AgNOj 5.812 gms. 



HNO 3 (sp. gr. 1.42) 250 c.c. 



Water to 1000 c.c. 



II. Starch Solution. Same as for method of Van Slyke and 

 Donleavy, see page 202. 



III. Potassium Iodide Solution. Same as that of Van Slyke 

 and Donleavy, see page 202. 



HEMOGLOBIN DETERMINATION 



Haldane's Method 1 



Principle. The hemoglobin of the blood is changed to CO- 

 hemoglobin and this diluted blood specimen is compared with a 

 standard solution of CO-hemoglobin. 



Procedure. With a 20 c.mm. pipette measure the blood into 

 the graduated tube containing a small volume of water. After 

 the blood has been added, but before mixing, a piece of glass tubing 

 connected with a gas jet is introduced into the free part of the 

 tube, so that air is instantly displaced from the tube. The gas 

 tube is then withdrawn while the gas is still flowing and the top 

 of the graduated tube at the same time quickly closed with the 

 finger. The liquid is then made to run up and down the tube 

 1 Haldane: Jour. Physiol., 1900-01, 26, 497, 



