Ward Rounds

to right heart failure, and is therefore a sign of impending disaster for many patients with common heart and lung diseases. We have known for a long time that hypoxia constricts lung vessels and causes pulmonary hypertension in acute experiments; this response may be important in disease as well. There are many theories about the mechanism of this hypoxic response, none of them generally accepted. Perhaps one of the most stimulating ideas in this book is Torrance's suggestion that further study of the hypoxic response of smooth muscle cells in lung vessels may give clues about the nature of chemoreceptor cells in general. Some other views on hypoxic vasoconstriction are discussed only briefly; this includes the recent work of Hauge and Lloyd, which suggests that chemical transmitters such as histamine may be important. The organizers of the conference invited papers on the interstitial space in the lungs, on vascular smooth muscle and its innervation, and on pulmonary hemodynamics, because this information might be relevant to pulmonary circulation problems. Much of this material is first rate in its own right, for instance D. F. Bohr's paper on smooth muscle, Catherine 0. Hebb's on motor innervation of lung blood vessels, and R. W. Torrance's on "The idea of a chemoreceptor." Evaluation of the impact of this work on pulmonary circulation research must clearly remain for the future, although the editors might have led the way in a summarizing statement. A postscript, outlining points of agreement and of controversy among the participants, would have helped the reader to arrive at some synthesis of all this diverse material. Although the absence of a general summary detracts somewhat from the book's value, as a source of specialized information on the pulmonary circulation it will remain unsurpassed until the next conference on that subject! AREND BOUHUYS