Page:The Harveian Oration,1902.djvu/32

 inhibitors, indicated by Schiff, were first clearly demonstrated by Bernard in 1858, in the chorda tympani. (Electrical irritation of the branch of this nerve distributed to the sub-maxillary gland was found to cause such a degree of vascular dilatation that the blood flowed from the veins in jets and arterial in hue — a condition entirely independent of the function of the gland as such, inasmuch as it occurs with the same distinctness when the function of the salivary gland has been paralysed by atropine. The phenomenon is a pure instance of vaso-dilatation.)

Bernard's discovery of the vaso-dilators of the chorda tympani was followed in 1863 by that of Eckhard of the vaso-dilator action of the nervi erigentes, and the existence of a special set of vaso-dilators running in separate channels from the constrictors was thus conclusively established. Subsequent researches have shown that vaso-dilators exist also in other nerves, which at first sight appear to contain only vaso-constrictors. Their presence, however, is only masked by the greater number