ELASTICITY OF MUSCLES. 



20 



Below the graduations the rod branches into two 

 arms, which again re -unite at a lower pointy and within 

 the space thus formed a scale- 

 plate is fixed for the reception 

 of the weights which it is de- 

 sired to apply. Finally the rod 

 ends in tw^o vertical plates of 

 thin talc standing at right 

 angles to each other, and these 

 are immersed in a vessel filled 

 with oil, so that, while offering 

 no obstacle to the upward and 

 downward motion of the ap- 

 paratus, they prevent any lateral 

 movement. In order to deter- 

 mine the extension of the muscle, 

 the graduated rod attached to 

 it must be observed through a 

 lens, and it must be noted which 

 divisional line of the graduated 

 rod corresponds with a thread 

 stretched horizontally across the 

 lens ; weights must then be ap- 

 plied, and the increase in length, 

 which declares itself by an alter- 

 ation in the relative position 

 of the graduated rod and the 

 thread, must be obser\^ed. Of 

 course, in calculating the ex- 

 tensibility from the figures thus 

 obtained, the weight of the ap- 

 paratus attached to the muscle must be taken into 

 consideration. 



Fig. 7. Du Bois-KKYMOxn's 



APPARATUS FOR THE 



STUDY OF ELASTIC EX- 

 TENSION IN MUSCLE. 



