7 CHAPTER XXXI. 



EXPERIMENTS ON MUSCLE (WITH RECORDS). 

 Extensibility and elasticity of muscle. 



Required: General stand with muscle chamber, drum, ten 10 R 

 weights (split lead), nerveless muscle preparation. 



Set up as follows : Attach the muscle by ifcs femur to 

 the clamp, and fasten the tendon by a silk thread to the 

 recording arm, clear of the aperture in the chamber floor. 

 Place moist blotting paper on the inner side of the glass 

 cover, and put the latter into position. 



Adjust the writing arm horizontally and set the pillar 

 arm against the stop ; apply the writing point to the drum ; 

 this adjustment should always be made near the paper 

 overlap. 



Suspend the hook, to carry the weights, from the writing 

 arm close to the muscle attachment. 



Turn the cylinder by hand for 2 or 3 cm so as to write 

 a short abscissa. Return to the starting point. 



Next add successive weights ; after each let the muscle 

 attain its full extension, and then move the recording surface 

 7 or 8 mm onwards before adding the next weight. 



The muscle will extend less with each additional weight. 



When all the weights have been applied, proceed to remove 

 them after the same fashion. 



The muscle will shorten by elastic reaction, which towards 

 the end is very slow in effecting complete restoration. 



Extensibility of muscle increases during 1 contraction. 



Required: General stand with muscle chamber, drum, inductormm, 

 Leclanche cell, 2 keys, 7 ordinary and 2 thin wires, nerveless muscle 

 preparation, ten 10 weights. 



