182 



EXPERIMENTAL PHYSIOLOGY. 



(b.) Make a nerve-muscle preparation, place it in a moist 

 chamber, attach it to a writing-lever, weight the latter with 

 15 grammes, and cause it to write on a drum revolving at a 

 moderate rate. 



Fig. To. Scheme of Arrangement for Tetanus. VS, Vibrating spring; 

 M, cup for mercury. Other letters as before. 



(c.) Fix the flat spring firmly in the clamp, with ten 

 inches projecting. Allow the drum to revolve, set the 

 spring vibrating, and while it is doing so, open the key in the 

 secondary circuit, and before the spring ceases to vibrate 

 short-circuit the secondary current. 



(d.) Shorten the vibrating spring somewhat, and repeat 

 the same experiment, making the tracing follow the previous 

 one. 



(e.) Make several more tracings, always shortening the 

 spring, until the tracing no longer shows any undulations, 

 until the spasms are completely fused i.e., until it has passed 

 from the phase of " incomplete " to " complete tetanus." 



Fig. 74. Curves obtained in previous experiment, the last almost a 

 complete tetanus. 



(/.) Finally take a tetanus-curve by introducing Neef & 

 hammer instead of the vibrating flat spring. 



(#.) Study the tracings. At first the tracings will be in- 

 dented, but gradually there will be more and more fusion of 



