The Function of the Sino-Auricular Node

Since the time Keith and Flack1(April, 1907) described and Koch2substantiated the presence and site of the sino-auricular node in the mammalian heart no experiments dealing with the physiology of this node have been attempted.3The earlier experiments which busied themselves with this subject were those of Langendorff and Lehmann4in 1906, Erlanger and Blackman5in 1907, and Hering6in 1907 and 1909. We desire to give a brief report of some experiments that have been carried on during the course of the past winter. It will be remembered that the so-called sino-auricular node has its location at the point where the superior vena cava enters the right auricle and is found just to the right of the right extremity of the right auricular appendix, and near its upper border. It is a structure of small size, roughly from 10 to 15