Page:The Harveian Oration,1902.djvu/21

 well-worn theme, I trust that in my endeavour to bring into line the various conditions, physical and mental, which influence the circulation, it will not be considered unworthy of my learned audience if I sketch the principal facts and stages in the development of our knowledge of this subject.

The heart and blood-vessels, together with the walls of the hollow viscera, glands and non-striated muscles of the hair bulbs, as well as certain striated muscles derived from the lateral plates of the mesoblast, are innervated by the great system of visceral or splanchnic nerves, the differentiation of which from the somatic, or those which supply the organs and muscles of animal life, is the distinguished merit of Gaskell. And it is gratifying to think that also to other countrymen than Harvey, notably Langley, we owe in large measure what is known respecting the distribution of the ultimate ramifications of this great system of nerves. The visceral nerves consist of two sets, possessed of opposite functions, viz., motor and inhibitory—terms which are applicable to their action on the heart, blood-vessels, and hollow viscera.