On the Regulation of the Blood‐supply of the Brain

ONE marked characteristic of the literature dealing with the cerebral circulation is, we think, the contradictory nature of the results which have been obtained by different investigators. There is no reason, we imagine, for doubting that the cause of these discrepancies is to be found in the great difficulty of avoiding the sources of error which plentifully surround the subject, and in overcoming certain technical difficulties which we shall presently have to refer to. The ease with which one can obtain results upon certain points, on taking up the subject, is itself, we believe, apt to make the inquiirer careless in controlling sources of error, which, it may be noted, are some of them not at first sigrht obvious. We must on this account say more about the technology of our subject than would be necessary were the subject a simpler one.