272 



THE BLOOD. 



placed over it. The brass plate is placed on the microscope, with 

 a magnifying power of 400 diameters. In a short time the red 

 corpuscles settle to the bottom of the cell, and the number con- 



S 



o 



o 



(J 







o 



o o 



o 



o 



D 



O 







c 







FIG. 145. Thoma-Zeiss hemacytometer. 1. Mixing apparatus: a, capillary 

 tube in which the blood is taken ; 6, chamber for mixing the blood with the 

 diluting solution ; c, glass ball to aid in mixing the blood with the diluting solu- 

 tion. 2. Cross-section of the chamber in which the blood is counted. 3. Section 

 of the field on which the blood is counted, showing thirty-six squares. 



tained in 10 squares are counted, added together, and multiplied 

 by 10,000; the product is the number in 1 cu.mm. of blood. 



Thoma-Zeiss Hemacytometer (Fig. 145). This is quite simple 

 to use, inasmuch as the blood is drawn and diluted in one in- 



