The volume represents the results and conclusions of more than thirty years of research on the origin, structure and function of the involuntary nervous system on the part of the late Professor Gaskell. Our present day knowledge of the involuntary nervous system is largely due to the fundamental pioneer work of Gaskell and his pupil, Professor Langley. The problems related to this nervous system are here treated in their widest biologic relations. The book will be of interest to the medical man, despite the fact that it takes no account of the rôle of the involuntary nervous system in disease, such as vagotonia, pluriglandular affections, etc. A clear conception of the biologic relations and rôle of this system in health must ever be the starting point in working out the complex behavior of the system in morbid processes.