410 



Dr. K H. Alcock. On the Rapidity of the [Oct. 20, 



convenient spot. The movement of the lever of the tambour was 

 recorded on a pendulum myograph, this serving to open the break key 

 in the primary circuit in the usual way. The strength of excitation 

 was 6000 units of the standard Berne coil, worked by a 4-volt 

 accumulator. 



This method presents the advantages of a muscle-nerve preparation 

 in a perfectly normal condition, and with a length of available nerve 

 from 290 380 mm., but requires the most careful attention to details. 

 It is necessary by preliminary experiments to ascertain (1) that the 

 rate of the pendulum is invariable within the limits of error required ; 



(2) that the break shock occurs always at the same place on the plate ; 



(3) that the height of each contraction as recorded by the tambour 

 shall be approximately the same : and (-4) to use the same tambour and 

 length of tubing throughout the series of experiments. 



FIG. 2. 



FIG. 2. Subject C.D. Four consecutive experiments. Each consists of a pair of 

 " near " and a pair of " far " excitations. 



