342 PEACTICAL PHYSIOLOGY 



EXPERIMENT XIII. a. To 1 c.c. of blood solution add 2 c.c. of phenol-phthaline 

 and hydrogen peroxide reagent. 1 Note the purplish-pink colour which develops 

 upon standing from 5 minutes to 1 hour. Ascertain in what degree of dilution 

 a blood solution will give this test. 



Another test for blood is the biological test (see chapter on Pre- 

 cipitins). 



The function of haemoglobin is to carry oxygen to the tissues. 

 This power of taking up oxygen can easily be demonstrated by 

 shaking up venous blood with air (see under Spectroscope). The 

 oxygen carrying capacity of blood can be ascertained as follows : 



EXPERIMENT XIV. In the bottle of a Dupre apparatus (see Fig. 242 

 in chapter on Urea) take 20 c.c. of oxygenated blood. Cover with 

 dilute ammonia. In the small tube take 5 c.c. of fresh saturated 

 potassium ferricyanide solution. Having adjusted the water to the 

 zero of the apparatus by means of the clip upset the ferricyanide 

 into the blood. Shake well. Readjust the level of the water and 

 read how much oxygen has been given off. 



CHAPTER IX. 



THE SPECTROSCOPIC EXAMINATION OF HAEMOGLOBIN AND 

 ITS DERIVATIVES. 



A SPECTROSCOPE consists essentially of a screen, in which there is 

 a small slit, through which light from any desired source can pass, 

 a prism, and a series of lenses forming the telescope, through which 

 the observer looks. 



For qualitative work the small direct vision spectroscope (Fig. 229) 

 is serviceable. When the position of the bands, however, is required, 

 one of the larger compound forms is necessary. 



Adjustment of the Spectroscope. It is necessary to have an exact 

 focus of the image of the slit. In the small direct vision spectroscope this 



1 This reagent is prepared as follows : Phenol-phthaline is added in excess (over 



032 grms. ) to 1 o.c. of ^NaHO. A little redistilled water is added. Shake well. 



10 N 



Filter. To filtrate add 20 c.c. j^NaHO and make up to exactly 100 c.c. with 



redistilled water. Add *1 c.c. of 3% commercial H 2 2 . This solution is best 

 kept in the dark. It may go faintly pink but not sufficiently to affect its value 

 in testing for blood. Water redistilled from glass should be used, ordinary 

 distilled water being distilled from copper. If this be used, the reagent will not 

 keep (Kastle). 



