(1. Continued contraction until marked fatigue results. 



Xdte difference l)et\veen voluntary tetanu- and tetanus due to 

 electric simulation. 



jo^. I'rmiiiction of (/(/</ /'/; muscle, a. On contraction. 1'ith 

 a frog and remove the skin from the hind legs. Stain these in 

 ph\ -iolo^-ical salt solution containing neutral red. Then stimulate 

 iinc leg with the tetanic current for _' or 3 minutes. Any change in 

 color: Xo\v place both legs in n 2<)(: XI I, < )| I in physiological salt 

 solution. Any difference between stimulated and unstimulated legs? 



1). ()n lictit ri</<'. Heat the unstimulated leg in the Xll,< Ml -alt 

 solution gradually till heat rigor sets in. Xote any change in color 

 and also in positi n of the leg as a \vhole. What do you conclude 

 a- to the relative -trength of the flexor- and extensor- of the leg? 



SMOOTH MUSCLE 



As material for experiment, rings about 3 mm. broad cut from 

 the -tomach of a frog or strips from a cat's bladder may be n-ed. 



204. Attach by hue copper wire one end to an L-shapcd gla-s 

 rod. the other to the >hort arm of a light muscle lever as in experi- 

 ment KJ'I. Immerse in Ringer's -olution and record any change- in 

 length on a very slow moving drum. 1 ); > you obtain rhythmical 

 contractions i r tone change-? Try raising the temperature of the 

 Ringer's solution to about 30 C. Ke-ult ': 



-'05. .Make appropriate electrical connections and study the 

 response of smooth muscle as under striated mu-cle. i Kxps. 

 [90-191. I 



HEART MUSCLE 



The properties of heart muscle will be examined in studying the 

 physiology of the heart (p. 8l). 



//. NERVE PHYSIOLOGY 

 \. XKKYK HI'.KUS. 



Stimulation of a muscle, -u-pendcd in a nioi-t chamber, through 

 it- nerve will give exactly the -ame type of contraction and mu-cle 

 curve a- direct stimulation of the mu-cle fibers thcm-clve-. 



Many of the fundamental phenomena of stimulation, however, 

 can be demonstrated to greater advantage on nerve. Muscle shows 

 irritability, conductivity and contractilit \ . Nerve -how- nly irrita- 

 bili;\ and c uductivity ; these \\\ > properties are interconnected and 



58 



