MECHANICAL RESPONSE OF. NERVE 



FIG. 314. Optical Kunchangraph for Record of Mechanical 

 Response of Nerve 



N, nerve chamber containing nerve with electrical connections, E E'. 

 Thread tied to lower end of nerve, and attached to short arm of optic 

 lever, O. Beam of light from L reflected from mirror of optical lever, 

 O, falls on recording-drum, D. Adjustment of reflected spot of 

 light made by micrometer screw, s. Periodic electric stimulation at 

 intervals of one minute is automatically made by means of key regulated 

 by clock-work. Air bubbles through water at w, and is led on by 

 india-rubber tubing, T, to nerve-chamber, thus kept humid. By 

 proper manipulation of stop-cock any vapour as chl or oform con- 

 tained in vessel v, may be passed through nerve-chamb er, subsequent 

 responses showing effect. 



