LESSON IX. WORK AND EXTENSIBILITY OF 

 MUSCLE. 



1. Make a sciatic -gastrocnemius preparation and a 

 similar preparation without the sciatic. Place in saline 

 solution. 



2. Work done by a contracting muscle. Fix the 

 nerve muscle preparation of 1 in the muscle chamber 

 and set up the apparatus for taking a single muscular 

 contraction. Put on a weight of 10 grams attached to a 

 long hook (Fig. 18). Adjust the point of attachment of 

 the muscle and the length of the lever so that the 

 magnification of the contraction is a whole number. 



Determine the position of the secondary coil which 

 gives a maximal contraction on break C 



of the primary, without being un- 

 necessarily strong. When once de- 

 cided upon keep the strength of 

 stimulus constant. Trace a base line 

 by moving the drum on about one 

 centimetre. 



Stimulate the nerve with a single 

 break shock, recording the contraction 

 on the stationary drum. Close the 

 secondary key, move the drum on 

 about half a centimetre by hand, add 



Fig. 18. Weights 



used for successive 



weighting of muscle 

 (reduced). 



another 10 grams weight, the muscle stretches, set the 

 lever horizontal, move the drum half a centimetre, and 

 stimulate again with a single break shock. Proceed in 

 this way till the load is 50 grams, then add 20 grams at 



