the height >f make and break contracti> n on a stationary 

 drum with gradually increasing stimuli moving the coils < cm. 

 closer at each trial, until both make and break shocks give maximal 

 -timuli. Kotate the drum by hand about 5 mm. betuccn each con- 

 traction record. Take also a tetanic contraction. Write on the drum 

 bel'U each contraction line the distance between the coils in centi- 

 meter-. Xote carefully any relation between height of contraction and 

 intensity of stimulus. What is the general law describing this rela- 

 tion : Compare the height of a single contraction with that of a 

 tetanus. l : rom the height of the curves ami the relative lem/tlis of 

 the two anus of the lever, estimate the actual distance throiii/h \chich 

 the muscle contracts, both In siiit/le twitch and tetanus. II hat pro- 

 portion of its o-^'ii Icin/th does the muscle contract in both forms of 

 contraction.' 



i'^. Influence of load on licit/Jit of contraction. Same arrange- 

 ment as in the preceding experiment. I'sc a fresh unexhausted 

 muscle. L'se the same stimulus (maximal break shock) through- 

 out. Attach the large weight pan to the lever and take contractions 

 with the following loads: I i ) unloaded, lever alone; ( _' I lever and 

 scale pan; 13 and foil, wing ( same + 10, 20, 30, 40, etc., grams 

 up to 100 gms. ; then increase by _><> gius. each until the limit ot 

 contraction is reached. Describe the relation between load and height 

 of contraction. Kstimate the work performed by the muscle in each 

 contraction in gram-centimeters. At which load is the work done 

 maximal? What is the absolute lifting power ("absolute force") 

 of the muscle stimulated by a single twitch? Is the lifting power 

 increased in tetanus? 



i</>. Influence of temperature on contraction. The muscle, is 

 fastened in the "muscle warmer" by binding the femur to the metal 

 rod with tine wire. The tendon of Achilles i< connected by a bent 

 pin and tine wire with the short arm of a special light muscle lever. 

 I 'lace a signal magnet in the primary circuit, and stimulate with 

 -ingle induced make' or break shocks. I'lace a thermometer lon-ely 

 in the "musi-le warmer" so that the fluid may be stirred occasionally 

 and the temperature maintained even. Sec 1 that the muscle is irritable 

 and then lower the temperature to 01 C'. but do nut frC( 

 lake a record of contraction on a rapidlv moving drum. I lien 

 raise the temperature slmvly and take records at 5 . l<> . 15 . 2O, 

 _>5 , 30 and 35 . Xote carefully the differences in licit/lit, dnrti'ion 

 and i/eneral form of co'itracti< n curve at the different temperatures. 

 \"te al-o tin- variation in the latent period with temperature. 



