SummaryAs I have stated in my 2nd2). 3rd. and 4th reports, respective brain‐wave change occurred with the injection of adrenaline, pilocarpine, and atropine the drugs known executing neuro‐toxic effects upon the aut nomic nerve. I classified the whole process into four periods based on the blood pressure change. Especially, in the case of adrenaline and atropine injection the average period, amplitude and time of appearance of a‐waves increased and decreased in parallel in 2nd and 3rd periods. In the atropine experiment there were certain number of subjects who presented diphasic increase and decrase in the 2nd period. On the contrary, in the case of pilocarpine injection, the average period of a‐waves showed the process just reverse to that of the average amplitude and time of appearance. When one reminds of that adrenaline is a sympathetic, atropine a parasympathetic paralyzant and pilocarpine a parasym‐pathitic stimulant, the results obtained here must be of great interest in illustrating the functional antagonism of the sympathitic and parasympathetic nerve system in the human body.As recently the problem of the peripheral and central functions have been taken up as important and as the locality of center of the autonomic nerve system is going to be assumed lying in dience‐phalon or more recently that of more important center up in the cerebral cortex, the effect of these drugs seems to have much to do not only with the peripheral functions such as the blood pressure, but also with the brain waves under influence of such central functions.The author here expresses his deepest appreciation to Prof. Dr.Misaoand Aeet. prof.Kimurafor their kind guidance and revision.This research work has been supported by Scientific Research Fund of the Department o