It is a common opinion among physiologists that the cerebral blood vessels do not possess effective vasomotor nerve control. The strongest evidence on which this opinion rests has been brought forward by a number of English physiologists, notably Roy and Sherrington,1 Bayliss and Leonard Hill,2 Hill and Macleod3 and Florey.4 Several Germans5 have also contributed evidence pointing toward the same conclusion. On the other hand, many important observations which are difficult to reconcile with this point of view have been reported by investigators from Germany,6 from France,7 from the United States,8 and elsewhere.9 Our own experiments bring new evidence in favor of the functional activity of vasomotor fibers in the blood vessels of the pia mater.
The question whether or not the cerebral vessels possess a vasomotor control is not merely of academic interest, for many clinical conditions such as convulsions