non-polarizable electrode- about one cm. apart, with the binding 

 posts .if one <il" tlu- ke\s i A ). Close the circuit through the muscle 

 for -cvcral minutes hy means of key I'., leaving key A open. \">w 

 <>pen key \\ and immediately make and lireak key A several time-. 

 l> es the mu-cle contract? \\'hcrc is the -ource of the current in 

 tliis experiment: The muscle act- as a delicate gal\ am mirter. 

 In what other way may a polarization current IK obtained? 



IV. CILIARY MOVEMENT 



J V '- I'ith a frog, destroying hoth hrain and spinal cord, and pin 

 it on it- hack on the frog hoard. Cut away the ventral body wall 

 and remove all of the viscera except the oesophagus and stomach. 

 With the scissor- cut through the lower jaw in the middle line and 

 continue the cut hack to the stomach. I )raw hack the flaps of the 

 lower jaw. and pin out the oesophagus to form a flat surface on a 

 level with the roof of the mouth. Keep the oc-ophagus and the 

 mucous memhrane of the roof of the mouth moist with normal saline. 



a. Lay one of the -mall pieces of cork on the exposed mucous 

 memhrane. In which direction does the cork move? Lay a weight 

 on the cork block and repeat the observation. Repeat again after 

 tilting the frog-hoard so that the weight must be carried up an incline. 



b. Remove the weight, and determine the time in seconds in 

 which the cork moves one inch. Make a second determination after 

 warming the preparation with saline solution at t }<> C. 



c. Saturate a piece of filter paper with ether and blow the funie- 

 d wn upon the preparation. After a few seconds make a third 

 determinate >n. 



(1. Similarly test the effect of vapor of ammonia, hut in this case 

 it will he sufficient to blow across the open mouth of the bottle. 



Record the re-ults of the four determinations. 



-'^7. ( )pen a clam, mussel or oyster shell and catch the contained 

 fluid in a beaker. Cut a small piece of tissue from the mantle, tease 

 it well with needles and mount under cover-glass. India ink may 

 be added to ascertain the direction of current-. Study and draw 

 under the high power various phases in the heat a- it becomes 

 -lowed through lack of oxygen. 1 >o yon see any individual cilia 

 heating which arc noi attached to cells. J 



J^S. Mount a piece of mantle on a slide between two noil polar- 

 i/able electrodes in sea water. I 'lace a cover-glass on the preparation 

 and study with the high power, \\hat i- the cited ot make and 

 break of the gaKanic current: Make and break single induced and 

 interrupted -In >ck- ' 



