Excerpt from The American Journal of Physiology, Vol. 17: Edited for the American Physiological Society; No; I. Issued September 1, 1906 Unless the intrinsic nervous system in the heart walls is thrown out of function it is obvious that any stimulus that affects the muscle cells will at the same time act on the nervous tissue. In fact, the nervous tissue may be more highly excitable than the muscle cells to many forms of stimuli, so that some of the reactions of the heart to direct stimulation may be caused by the stimulation of the nervous tissue alone. It would then seem obvious that as yet we do not know the properties of the heart muscle in the vertebrates apart from the intrinsic nervous tissue. 1 It may be that the peculiarities revealed by the response of the heart to direct stimulation are due to the peculiar properties of the heart muscle, but it is also possible that they are due to the peculiar properties of the intrinsic nervous tissue in the heart and to the physiological interaction between the two tissues. Direct proofs are lacking in support of either view. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.