Licence: In copyright
Credit: Arterial hypertonus, sclerosis and blood-pressure. Source: Wellcome Collection.
Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.
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![system to the nervous system have been traced and deter- mined hy long and careful experimental investigation. The investigation of these relations has been so detailed, and the results have been so striking, that teachers, and through them students and practitioners, have almost come to regard the vessels as the toy of the nervous system,—that their manifestations merely mirror nervous influences. The effect of various emotions upon them was too apparent and too assertive to escape observation, or not to demand recognition. The path by which emotion travelled was traced, and the controlling power of the vasomotor centre in the medulla was determined. The result has been that the vaso- motor mechanism thus revealed has appealed so strongly to the medical imagination that the play or movement of the arteries has been thought of through the nervous sjstem only ; as if they had no identity, as if they were the mere weather- cocks of every gust of nervous influence, the bond-slave of the higher system. The nervous side of the vasomotor mechanism 1ms been regarded as supreme; as instigating, regulating, controlling, and determining all vascular phenomena, even those attendant upon the activities and exhaustions of organs and tissues. The names of Claude Bernard, Brown-Sequard, Waller, and Schiff are “ household names ” in this con- nection. I ]ieed not dwell at length on the achievements of physiological investigation in this department; they are well known, and I have indicated that they have not hitherto been underrated. Their very brilliance has, I ventnre to think, seriously blinded us to the fact that physiological investigation has also shown that Jthere is another factor which influences and determines the move- ment or play of the vessel wall; tliat factor being t^he compositipip of the circulating fluid itself. It is with this factor that I mainly deal in these pages, and I hope to show that the failure to ap})reciate aright this aspect of the circulation lias iirevented our understanding many things; while its recognition makes many things clear. I hope to show that the prevalent view is too exclusive, is incomplete, and correspondingly inaccurate and misleading.](https://iiif.wellcomecollection.org/image/b28036591_0062.jp2/full/800%2C/0/default.jpg)
