52 LABORATORY METHODS OF 



2. Observe the position of the heavier materials in 

 the blood. 



3. Hold the instrument between you and the light; 

 see how far the red cells register on the graduate. 

 This is a tube of small bore and is arbitrarily gradu- 

 ated. It registers per cent. 



Exercise No. 34. Make a spread of frog's blood. 



i. Snip the nose of the animal with a sharp instru- 

 ment and obtain a small drop of blood. 



FROG'S BLOOD. 

 1, Leukocytes; 2, oval red cells. 



