The approach of this treatise is physiological throughout. In the eyes of the author it answers the rhetorical question raised by Maurice B. Visscher at the Physiology Congress in Washington D. C. in 1968: Does physiology exist? What he meant by this question was whether the fields of cellular physiology and physiology of the various organ systems had become so large that physiology as such had vanished. The firm answer is that physiology does indeed exist. Although it is important to study physiological problems at the subcellular level, it is importan- and equally difficult - to study organ...