EXERCISE 84 

 OF WHAT DOES THE BLOOD CONSIST? 



Materials. A compound microscope ; a cover glass ; vaseline ; a needle ; alcohol. 



Directions. This experiment should be done by the instructor as a demonstration. Sterilize a 

 sharp needle by holding it in a flame for a few moments. Wash the ball of the middle finger of 

 the left hand with alcohol. Tie a piece of cloth quite securely around the first joint, and then 

 with a quick thrust of the needle puncture the skin. A drop of blood will quickly collect. This 

 should be transferred to a glass slide. A cover glass which has had vaseline applied to its edges 

 should be placed over the drop in order to seal it. Can you distinguish the liquid of the blood from 

 the solid bodies (corpuscles) ? What is the nature of the corpuscles ? Where is most of the coloring 

 matter of the blood ? 



Additional problem. If prepared slides with corpuscles properly stained are available, make a detailed 

 study of both red and white corpuscles, and make drawings to illustrate their structure. 



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