20 Life and Health 



ADDITIONAL EXPERIMENTS 



It may be well to postpone some of the experiments in histology 

 until kindred topics are met with in the succeeding chapters. 



For general directions and explanations and also suggestions for 

 performing additional experiments, see the Appendix. 



Experiment 5. To examine adipose tissue. Take a bit of fat 

 from the mesentery of a rabbit. Tease the specimen in salt solution 

 and mount in the same. Note the fat cells lying in a vascular 

 meshwork. 



Experiment 6. To examine blood corpuscles. Wind a piece of 

 twine tightly around the last joint of a finger. Prick the skin with a 

 clean needle. A drop of blood will flow. Spread it out on a piece 

 of glass under a cover-glass and examine with the compound micro- 

 scope. A large number of red corpuscles may be seen and a few 

 colorless cells. 



Experiment 7. To examine a typical nucleated cell. A colorless 

 human blood corpuscle is a typical nucleated cell. Dilute a drop of 

 fresh blood (to be obtained and examined as directed in the preced- 

 ing experiment) with water, or, still better, with very dilute acetic 

 acid. The spongy protoplasm of the colorless corpuscles swells 1 up 

 and becomes, transparent. An internal rounded body becomes visible, 

 which is the nucleus. 



When the blood under the microscope is stained with carmine fluid, 

 the nucleus is generally more deeply stained than the rest of the cor- 

 puscle. This may be done by placing a drop of carmine fluid on 

 the slide close to the edge of the cover-glass and pressing a piece of 

 blotting paper against the opposite edge of the cover-glass to absorb 

 a little of the liquid. 



NOTE TO THE TEACHER. The teacher is advised to use these 

 two most excellent handbooks : Peabody's Laboratory Exercises in 

 Anatomy and Physiology (H. Holt & Co.) ; Brown's Physiology for 

 the Laboratory (Ginn & Company). 



Reference should also be made to the Outline of Requirements 

 in Anatomy, Physiology, and Hygiene for admission to Harvard 

 University. 



