APPENDIX I. 107 



which the liquid metal speedily reassumes its sphe- 

 roidal surface. So that when the amalgamated point 

 comes down again, it cannot reach the mercury, and 

 the chronoscopic circuit remains open. 



In order to obtain a clear insight into the condi- 

 tions of the experiment, it should first be made by 

 stimulating, not the nerve, but the muscle itself. 

 For this purpose, the ends of the secondary coil 

 should be united with the wires 1 and 2 in the 

 diagram. As, on doing so, all the parts of the 

 muscle are acted upon simultaneously at the* very 

 instant the chronoscopic circuit is made, no delay 

 in the nerves can occur ; nevertheless, a deflection 

 of the needle is thus obtained, which shows that 

 after the stimulation there is an interval of time of 

 about '01 of a second, during which the tension of 

 the muscle still remains unaltered. This interval 

 has been styled by Professor Helmholtz the stage of 

 latent stimulation. 



If, after having made the muscle support the 

 lever so that it just rests on the plate p, a weight be 

 placed upon the scale-pan, the deflection obtained 

 on stimulating the muscle as before is increased, 

 and, up to a certain limit, the more so the heavier 

 the weight. It thus appears that after the stage of 

 latent stimulation is over, the muscle does not at 

 once acquire its whole energy, but that its tension 

 (at equal length) gradually increases, and reaches 

 its maximum after about -05 of a second. 



This result (which the speaker illustrated by two 

 experiments, one without, and the other with an 

 additional charge on the scale-pan) is in itself of 



