The scientific literature has expanded dramatically in recent years, making entry into the structure of any given area extremely difficult; concurrent with this explosion more people are required to become acquainted with information outside their main line of expertise. For this reason there is a need for review articles which give an overall review of circumscribed areas. This volume reviews the subject of respiratory control mechanisms; the authors of each chapter are active research workers engaged in the area covered by their chapter. The first four chapters are concerned with the basic physiological mechanisms which sense changes in the respiratory system, in the standard physiology textbook parlance chemical and neural sensory receptors. The peripheral arterial chemoreceptors sense changes in arterial oxygen tension, carbon dioxide and pH. The first chapter describes the basic responses in the organ produced by changes in blood chemistry. Later chapters discuss changes in activity produced by exercise, chronic hypoxia and the possible role of the chemoreceptors in initiation of respiration in the new-born. In Chapter 1, a section considers the action of drugs on the peripheral chemoreceptors, and finally there is a discussion of the possible mechanisms whereby the organs sense changes in blood chemistry. This pattern is followed in subsequent chapters wherever possible; first a discussion of the basic physiological properties, followed by any clinical application and dis cussion of the mechanism whereby the receptor might operate. The remaining chapters are of a more applied nature.

According to Valentin (1833) and Luschka (1862), the first description of the structure now known as the carotid body must be ascribed to a Swiss physiolo gist - Albrecht von Haller - who, in 1762, called it the ganglion exiguum. This claim, however, may be erroneous, for Tauber (1743) described a struc ture at the bifurcation on the common carotid artery and called it the ganglion minutum. Andersch (1797) reprinted the text of a study made by his father between 1751 and 1755. The original printing of this work had apparently been sold as waste paper Andersch called the organ the ganglion intercaroticum on account of its location. He also specifically stated that the sympathetic chain, the glossopharyngeal and the vagus nerves sent branches into the organ. For a while the carotid body remained forgotten, to be rediscovered in 1833 by Mayer of Bonn who again remarked upon the branches of the sympathetic, glossopharyngeal and vagus nerves as sources of a nerve plexus which innervated the ganglion intercaroticurtl. . Valentin (1833) clearly regarded the structure as part of the sympathetic nervous system, although he too recognised that the vagus and glossopharyngeal nerves contributed conspicuously to its innervation. Thus it is evident that the anatomists of the eighteenth and early nineteenth centuries regarded the structure in the carotid bifurcation as one of the many ganglia which are interspersed in the course of the sympathetic nervous system."