PHYSIOLOGICAL H&MATOLOGY. 269 



both red and white corpuscles at the same time instead 

 of counting separately as in Lessons LVI and LVII. This 

 is important to determine the relative proportion of red 

 to white, or white to red corpuscles. 



Precautions, Extra care must be exercised in cleaning 

 pipette after the use of this staining solution. 



Observations. 



(1) Compare the results of this method with those 

 obtained in counting red and white corpuscles separ- 

 ately. 



(2) Determine the proportion of white to red corpuscles 

 in a number of normal individuals. 



(3) Has age any influence on the proportion? 



(4) Has sex any influence on the proportion ? 



(5) Has the general condition of the nutrition any in- 

 fluence ? 



(6) Is the proportion always the same in one individual? 

 If not, is there any periodicity in the changes ? 



(7) Determine, if possible, the causes of the variation. 



