110 APPENDIX I. 



beginning, and the successive stages, of the contrac- 

 tion ; wherefore the apparatus employed is termed 

 a myographion. To this end, opposite a steel point 

 or style suspended from the lever is placed a 

 rotating cylinder of glass, blackened over a lamp. 

 The cylinder is moved by clockwork at an increasing 

 rate, and, when it has acquired the proper speed, 

 the centrifugal force developed releases a piece of 

 mechanism which breaks the primary circuit of the 

 induction apparatus connected with the muscle or 

 nerve. In consequence of a very ingenious arrange- 

 ment, which will hereafter be explained, this always 

 happens when the cylinder is in exactly the same 

 position to the style ; so that always the same point 

 of the datum-line traced by the style during the 

 quiescent state of the muscle corresponds to the 

 instant of stimulation. 



The contracting muscle thus traces a curve on 

 the cylinder, like those in Fig. 2. The point s of 

 the datum-line marks the instant of stimulation. 



FIG. 2. 



The curve does not start from this point, but a little 

 later, from m, the distance 8 m corresponding to the 

 stage of latent stimulation, if we suppose the muscle 

 to have been acted upon directly by the current. 

 The muscle then, slowly and gradually, begins to 

 act, in due time reaches a climax of energy, and 



