112 



PHYSIOLOGY OF MUSCLES AND NERVES. 



the end of the rod, and thus driving' the frame with the 

 rods from B to J., in a direction opposite to that of the 

 arrow on the indicating pkxte, a point is reached at 

 which the 'trigger' which is seen on the standard A, 

 and which acts upward, fits into a corresponding notcli 

 in the rod at a, thus preventing the re-extension of the 

 spring. It therefore remains compressed till pressure 



Fig. 28. Spuing Myograph, as used by du Bois-Eeymond. 



on the trigger frees the frame, which then traverses the 

 whole length of the wires at a speed depending on the 

 strength of the spring, &c., in the direction from A to B, 

 that indicated by the arrow. 



In order to describe the muscle-pulsation on this 

 plate, side by side with it there is a lever with an 

 indicating pencil, such as wjis used in the former ex- 

 periment, to indicate the height of muscular elevation 



