LESSON II. 



STRUCTURE OF THE BLOOD AND LYMPH 

 CORPUSCLES OF THE FROG. 



1. A frog is given you the brain and spinal cord 

 of which have been destroyed (cp. p. 330). Take the 

 frog in one hand, and with a stout pair of scissors 

 cut off a foot at the ankle-joint. Touch a clean slide 

 with the cut surface, so as to leave a small drop of 

 blood on the slide. Place on it a cover-slip. 



Later, drops of fresh blood should be obtained by 

 cutting off the other foot, the leg at the knee, the fore 

 arm at the elbow-joint. Lastly, blood should be obtained 

 direct from the heart ; in order to do this cut through 

 the skin in the median ventral line, cut transversely 

 through the lower part of the sternum just above the 

 epigastric vein, with stout scissors cut through the 

 sternum in the middle line and so expose the heart; 

 cut off the tip of the ventricle, and touch a slide with 

 it. For 5, 6, 8, blood which has flowed from one of 

 the cut surfaces will serve. 



Examine the mounted drop of blood under the 



