128 PHYSIOLOGY FOR THE LABORATORY. 



I. PERCEPTION or TEMPERATURE. 



a. Close the eyes and have some person touch different 

 parts of the body with cold and warm rods. How are the 

 sensations different? 



b. With fur, wood, and metal of the same temperature 

 test the body. Which feels colder? Why? 



II. ESTIMATION OF TEMPERATURE. 



Plunge the hand into water of different temperatures 

 and so learn to judge the temperature of water. How hot 

 can you endure the water? Can the hands or the feet 

 endure warmer water? Plunge one hand into hot water, 

 the other in cold, and then both into warm water. What 

 is the sensation in each hand? 



C. The Sense of Pressure. 

 Apparatus. Weights of different sizes. 



ESTIMATION OF WEIGHTS. 



a. Lift weights of different magnitude until you are 

 able to judge some of the more common, as a pound, 

 three pounds, etc. 



b. Hold a pound weight in the hand. Add a few 

 ounces. What is the least difference that you are able 

 to perceive? 



D. The Senses of Taste and Smell. 



Materials. Sugar, vinegar, salt, pepper, apple, potato, onion, 

 ammonia, and cabbage. 



