We have in the consideration of the influence of the emo tions upon the blood-vessels anticipated, to some extent, the fundamental principle of this section. The important part played by the vaso-motor nerves was there dwelt upon, chiefly in connection with the vascularity of the skin, which so manifestly results from emotional excitement. The circulation of the blood through the various organs of the body being affected by the same cause, the action of the emotions in inducing well-marked changes in nutrition and secretion is not extraordinary. But the question which at once arises, whether these variations in the circulation of the blood in the organs and tissues, adequately account for the alterations in nutrition and secretion, now referred to, deserves some consideration here.