ACTION OF REAGENTS ON RED CORPUSCLES. 237 



of the best known methods is that of Malassez, the details of 

 which are as follows : 



Blood is drawn into the capillary tube of a specially prepared 

 delicate pipette (Fig. 104, A) up to a mark which indicates y^j- 

 part of the capacity of the pipette. This known quantity of 

 blood is then washed into the bulb of the pipette by drawing up 

 artificial serum to fill the bulb, where the fluids are mixed by 

 shaking about the fine bead contained in the bulb. Some of this 



FIG. 105. 



The appearance presented by the Capillary Tube of Malassez's Apparatus when filled 

 with diluted blood and examined under a microscope magnifying 100 diameters pro- 

 vided with an eye-piece micrometer. 



mixture is then allowed to pass into a flattened capillary tube of 

 known capacity fixed on a slide, and the number of corpuscles in 

 a given length of this tube at two or three places is carefully 

 counted. The important question, how much oxy haemoglobin 

 exists in a given sample of blood, can be determined by diluting 

 a drop until the color equals that of a standard solution of known 

 strength. 



