THE SPINAL CORD AS A REFLEX CENTRE :;.',; 



and that in certain cases there maybe increased delay in the spinal cord. When tin- 

 latencies of the knee-jerk and the homonymous flexor reflex are compared by tin- 

 electrical method, it is found that the latter is roughly double the former, the average 

 latency of the knee-jerk in the spinal cat being 6-60-, and of the homonymous flexor 

 reflex 13-2<r. Jolly suggests that this difference may be due to the fact that the knee- 

 jerk mechanism involves only one spinal synapse or set of synapses, while the flexor 

 reflex may involve two. In these estimates the rate of conduction in mammalian nerve 

 has been taken at 120 metres per second. 



