NORMAL HMMA TOL OGY 



143 



which has a white substance in the sealed end of the tube containing 

 the colored solution ; the other is for use with artificial light and has 

 a black substance in the sealed end of the tube (Fig. 70). 



Appliances. Gowers' hsemoglobinometer and a glover's needle. 



Reagents. Distilled water, hydrogen peroxide, alcohol, and ether. 



Preparation. Clean the instruments in the usual manner. The 

 capillary pipette should be cleaned with the same care and in the same 

 way as the diluting pipette, being careful to first clean and then to 

 dry the pipette. Fill the graduated tube to the mark 20 or 30 with 

 distilled water; prepare the needle and finger or ear as usual. 



Technique. Obtain the blood in the usual way except that a 

 larger quantity of blood is needed than for the preceding instru- 

 ment. Hold the ear in the same way and fill the pipette as when 



FIG. 70 





Gowers' hsemoglobinometer : 1, blood capillary; 2, solution of standard color ; 3, tube in 



which blood is diluted. 



obtaining blood in the pipette for counting corpuscles. Wipe away 

 the first drop of blood. Touch the tip of the pipette to the drop of 

 blood, resting the pipette on the end of the thumb, which is behind 

 the ear, and slowly suck the blood up to the mark on the pipette, 

 but do not allow the blood to go beyond that point. If the drop is 

 not sufficient, quickly obtain the second drop by gentle pressure 

 high above the wound in the ear. If there is any excess of blood 

 on the point or sides of the pipette, quickly wipe it away. Insert the 

 pipette into the tube almost to the water and slowly blow the blood, 

 drop by drop, into the water. Now immediately shake the tube to 

 mix the water and blood; this is to prevent the blood clotting or 

 remaining as a thread in the bottom of the tube. Blood still remains 

 in the capillary on its sides; so fill the pipette with distilled water and 

 blow this into the tube, three or four times. Then thoroughly mix 





