As in previous editions, practical instructions have been printed in italics, and theoretical statements in Roman type. The latter take the form of brief introductions to the majority of the chapters in the qualitative section. Students are advised to read these introductory sketches before carry ing out the corresponding practical work. The writers have included this small amount of theoretical material with the object of aiding students in correlating information gained from lectures or reading with that acquired experimentally. To further this aim, references to readily accessible text books and other literature have been freely inserted. It is hoped that these references may also prove useful for students desiring more complete information on certain topics.
The rapid progress of physiological chemistry, and the ever increasing accumulation of methods render the task of selecting material a difficult one, and the selection given in this book is probably in many respects open to criticism. The writers regret that the subjects of gas analysis as applied to physiology and of dynamical as distinguished from descriptive physiological chemistry have received inadequate treatment. A satisfactory account of these subjects would have entailed an undue increase in the size and cost of the book.