ON THE MAMMALIAN NERVOUS SYSTEM. 



497 



The ordinary reflex is produced by the stimulating electrodes being applied to an 

 afferent nerve, the posterior root at B, and the effect recorded by contraction of the 

 muscle M. If the distances BA and EM are known, and the latency delay in the 

 muscle, then it follows that by subtracting these from the total time expended in the 

 execution of the phenomenon we obtain a residue which is the actual delay of trans- 

 mission of the excitatory effect within the centre EA itself. 



This we have done as follows : 



SIMPLE Reflex Delay, two Experiments (Cat). 



1. Total expenditure of time between excitation at B and 



contraction at M 



2. Time expended in transmission from B to A and E to M at 



33 metres per second : . . 



3. Time expended in latency of muscle at M 



Second. 

 022 



006 

 01 



The sum of 2 and 3 gives all the time expended in extrinsic duties ; the subtraction, 

 therefore, of these from 1, gives the delay or loss of time in the centre itself; this 

 amounts to '006 (in one case - 004). 



We now turn to what is more interesting, viz., the loss of time when the impulse 



MDCCCXCI. B. 3 S 



