INTERACTION AMONG REFLEXES 827 



tering the cord as motor fibers leaving it, but also that each afferent 

 fiber, after its entry to the cord, gives off several collaterals, each of 

 which runs to some nerve center in the cord (see Fig. 207). 



Certain conditions may break down the path along which the impulse 

 passes; for example, at a certain stage in the action of strychnine all 

 pathways become opened up, so that the reflexes which ordinarily do not 

 occur together, act simultaneously, with the result that a typical convul- 

 sive movement is produced. Strychnine, as we have already seen, also 

 interferes with the sorting out of the impulses into inhibitory and ex- 

 citatory, so that no reciprocal action occurs. 



