56 EXPERIMENTAL GENERAL PHYSIOLOGY 



(a) To determine the amount of work done by a single contraction. 



(1) What weight is lifted? 



(2) How high is it raised? 



(3) What is the ratio between the height of the curve traced by 

 the lever and the height through which the weight was raised? 



(4) Let JF=work done. 



g= weight lifted. 



h = height of curve traced by lever. 

 k= constant of the apparatus, in this case the ratio 

 between the lever arms. Then W=k. g. h. 



(5) Express the amount of work in ergs. 



(b) To determine total work done. 



(6) How many times was the weight lifted before the muscle 

 was fatigued? 



(7) Through what average height was the weight lifted? 



(8) Has the value of k or g changed? 



(9) Give a formula for total height (H=). 



(10) Give a formula for total work done (W=). 



(11) Express in ergs the total work done by the muscle. 



(12) In the fatigue tracing, did the lever continue throughout 

 the observation to fall back to the original abscissa? If not, describe 

 the general changes in the abscissa. 



(c) Reaction changes. 



(13) Apply a piece of neutral litmus paper to the fresh muscle 

 tissue of the frog from which your specimen was taken. Record 

 result. 



(14) Apply a piece of litmus paper to a fresh-cut surface of the 

 fatigued muscle. Record results. 



(15) What is the reaction of a muscle of a frog after rigor mortis 

 has been established? 



(16) What is the reaction of fresh urine? 



(d) Secondary fatigue (Lagrange, p. 60). 



(17) Grind a fatigued or exhausted muscle in a mortar and extract 

 with normal saline solution. 



(18) Inject this extract into subcutaneous lymph spaces of a frog. 



(19) Observe the effect of this injection upon the second or 

 rested frog. 



(20) Observe the effect upon the working power of its muscles. 



XIV. TO SEND AN ELECTRIC CURRENT INTO A NERVE WITH- 

 OUT RESPONSE. FLEISCHL'S RHEONOM. . 



When one is observing the effects of mechanical and thermal 

 stimuli, he finds that he may apply a mechanical stimulus so slowly 

 that the nerve may be severed without calling forth a response; he 



