LESSON I 



MUSCLE AND NERVE 

 AMEBOID AND CILIARY MOTION. METHODS OF STIMULATION 



1. Ameboid Motion. Place a few drops of a hay infusion upon a 

 glass slide. Bring a large and active ameba into the field of the micro- 

 scope. Observe carefully the behavior and position of the organism, 

 making drawings of its shape at regular intervals. Add a few granules 

 of India-ink to the medium and observe how these particles are engulfed. 



2. Protoplasmic Streaming. Examine with the low power of a 

 microscope a leaflet of a fresh specimen of nitella. Observe the move- 

 ment of the protoplasm. What part of the cell is in motion? In which 

 direction does the flow take place? How is the movement changed by 

 mechanical stimuli? Note the effect of warmth upon the movement. 



3. Ciliary Motion. Etherize a frog and destroy its brain and spinal 

 cord. Place the animal upon its back. Make a median incision through 

 the lower jaw, and retract the segments laterally. Place a small piece 

 of cork upon the mucous surface between the eyes. Moisten the sur- 

 face with normal saline solution, if necessary. Note how the piece of 

 cork is gradually carried by the action of the cilia toward the esophagus. 

 Determine its rate of movement. Moisten the surface with normal 

 saline solution the temperature of which has been raised 2 or 3 degrees 

 above that of the room. Note the effect upon the movement of the 

 cork. 



Tilt the plate upon which the frog is resting until the cilia are no 

 longer able to move the piece of cork. Hold the plate horizontally and 

 put small bits of lead upon the cork until one is found which the cilia 

 are unable to propel. What is your idea regarding the strength of these 

 structures? 



Place a small segment of the gill-plate of a fresh clam upon a slide 

 for microscopic observation. Straighten its edge and immerse the 

 entire preparation in a few drops of the fluid obtained when the shell 

 of the clam was opened. Study carefully the action of the cilia at in- 

 tervals, and especially later on, when their movement has been consider- 

 ably slowed so that single cilia may be clearly made out.. What is the 

 position of the cilia when at rest and when contracting? Apply normal 

 saline solution which has been slightly heated (25 C.). Note its effect 

 upon the rapidity of the movement. 



4. Structure of the Different Types of Muscle Tissue. Unless still 

 quite familiar with the general structure of non-striated, striated, and 

 cardiac muscle, examine preparations of these tissues under the micro- 

 scope. Study the action of the myoids in stentor or vorticella. 



21 



