GENERAL PHYSIOLOGY. 49 



(2) Find and mark the position which the rotating 

 limbs occupy when the detector needle indicates 10. 



(3) Find and mark in succession each higher incre 

 ment of 10 until the maximum is reached. 



(4) Rotate the limbs so gradually as to cause the de- 

 tector needle to rotate with slow and regular motion 

 from the zero position to the maximum position and 

 back. 



(5) Make a gastrocnemius muscle nerve preparation; 

 mount it in the muscle telegraph; change the wires 

 from the detector to the electrodes of the muscle 

 telegraph; place the limbs of the rheonom in the 

 maximum position, close the key. With the closing 

 of the key the maximum current is instantly thrown 

 into the nerve and serves as a strong stimulus in 

 response to which the muscle contracts. 



(6) Place the limbs of the rheonom in the minimum 

 position. Close the key. Inasmuch as the muscie 

 nerve preparation is much more sensitive to elec- 

 tricity than is the low resistance detector the muscle 

 will probably respond when the conditio-ns are as 

 above indicated. Theoretically a zero point exists. 

 Practically it is difficult to find it for a muscle- 

 nerve preparation. The finding of a position where 

 there is no response on closing the key is however not 

 essential in this experiment. 



(7) Keeping the key closed, slowly rotate the limbs 

 of the rheonom from the minimum position to the 

 maximum position. If the conditions are favorable 

 this can be done without calling forth a response. 



(8) Without opening the key, slowly rotate the limbs 

 backward from the maximum to the minimum posi- 

 tion. One may thus send through a nerve a strong 

 current and may withdraw the same without caus- 



