This monograph is the first of a series which is designed to present in depth timely reviews of subjects related to the blood. Insofar as each subject lends itself, the clinical aspects of each topic will be presented as fully as is appropriate, in addition to the basic features. As a consequence, the various monographs should be found useful not solely by hematologists. Depending on the nature of each topic, it is expected that these monographs will be found important by physiologists and specialists in fields other than hematology, as well as by scientists of very diverse interests. The present treatise illus­ trates this point. Doctors Garby and Meldon have brought together in a most useful way the spectacular advances which have been made in the last decade or two in a field of fundamental biologic impor­ tance. They have also brought to the discussion of this subject their own observations and interpretations as well as their profound understanding of the respiratory functions of the blood. Maxwell M. Wintrobe Salt Lake City, Utah v Preface This volume is an attempt to summarize the present state of know­ ledge of the respiratory functions of blood in health and disease. Though it deals fairly thoroughly with physicochemical aspects of the blood's gas transport properties and with the molecular chemis­ try of hemoglobin, its main emphasis is the gas transport function of the blood in vivo and modes of its disturbance in disease.