Preface 



The section on the circulation of the Handbook of 

 Physiology is offered in three \olumes. The first of 

 these was planned to cover the physiology of the 

 heart and its controls, along with certain material 

 about the volume of the blood and the biophysical 

 background of the organs of the circulation. The 

 second volume was planned to include the functional 

 morphology of the vessels and their coordination in 

 regulating the distribution of blood flow to the ses-eral 

 organs. The third volume was planned to deal with 

 the circulation as the functions of an organ system 

 wliose normally coordinated or abnormal action plays 

 upon the organism as a whole. 



This original plan has been modified somewhat in 

 the interests of prompt authors and at the expense of 

 tardy ones. Some have advanced into Volume I; we 

 hope that some chapters originally scheduled for 

 \'olume I may be fitted into the later ones. 



The circulation is a subject whose ramifications are 

 protean. Not only does it have an intrinsic regulation 

 feeding back from the circulatory organs themselves, 

 but changes in the circulation alter the functions of 

 other organs which in turn \vork new changes in the 

 circulation. Another complication in dealing with the 

 phvsiologv and biophysics of the circulation is the fact 

 that certain fields are in vigorous controversy. 



It is to be expected, therefore, that some topics will 

 be covered more than once by different authors. We 

 have tried to provide that the two coverages are not 

 mere repetitions and a great deal of material has been 

 discarded for this reason. On the other hand if the 

 o\erlap is not really an overlap, but shows the ma- 

 terial or argument in different context, from different 

 viewpoints, and with different interpretation, the 

 outcome seems to us to be good. 



Each chapter is written in the hope that it will be an 

 authoritative systematic account of the present status 



of the field and a contribution to Physiology as a 

 science in its own right. The chapters are as detailed 

 as over-all space will permit. Coverage of all the 

 literature is not attempted. Citations are restricted, 

 for the most part, to the factual esidence and theoreti- 

 cal interpretations that bear upon concepts that are 

 seriously advocated at the present time. Recent con- 

 tributions are not allotted space because of their 

 recency, but only as they are constructive of current 

 ideas. 



Each chapter is written to fit the needs of three 

 groups of readers: i) the graduate student who wants 

 to go more deeply and broadly into the meanings of 

 current physiological concepts and their background 

 than he can in standard text books; 2) the teacher who 

 is dissatisfied with the comprehensiveness of his under- 

 standing outside his own specialty; and j) the in- 

 vestigator who will use it as a springboard for refer- 

 ences and current concepts in a field which he is 

 beginning to explore. The contributions are written 

 bv qualified experts, modern in \iewpoint, and 

 emphatically are not esoteric polemics between 

 specialists. 



In selecting these specialists, adx'ice was sought on 

 an international basis. One of us met in Ghent with a 

 committee of representative European physiologists 

 selected and chaired by Prof. C. Heymans. This group 

 gave valuable advice concerning our tentati\e chapter 

 list and nominated authors for each of the chapters. 

 This editor also met with a similar group in London, 

 selected by O. G. Edholm and Prof. J. McMichael. In 

 the hands of these men the plan was further revised and 

 additional authors were nominated. The final selection 

 of authors and alternates and the final revision of the 

 plan were made by an ad hoc committee accepted by 

 the Board of Publication Trustees and composed of 

 knowledgeable members of our own Societv. The 



