~espjrutj~~ Physiology (1977) 30, 3-S @ Elsevier/No~h-HoIland Biomedical Press
FOREWORD
This issue of ~~~~~~~ti~~P~ys~~~~gyis dedicated to Hermann Rahn, imaginative investigator, teacher and mentor, friendly but incisive critic, physiologist par exceilence. The articles were written by some of the collaborators, and by students privileged to have worked with Dr. Rahn, an opportunity that was usually decisive for their careers. His encouragement - and his ideas - were of crucial importance in directing the authors’ early work, and his outstanding qualities have left a lasting mark on all those who benefited from his direction. Dr. Rahn’s broad interests cannot be adequately reflected in any one specialty journal, but since the field of respiratory physiology will forever bear his imprint, it is appropriate to honor him in these pages. Born in East Lansing, Michigan, in 1912, Dr. Rahn grew up in a family of nature lovers. His father, an eminent bacteriologist, early introduced him to the value of careful observation and the joys of collecting, habits evident today to anyone walking or driving with Dr. Rahn for half an hour in the countryside. Seeing the remarkable in nature, and following up with the right questions, form the basis of the extraordinary, often colorful variety of physiological problems he later examined. Hermann Rahn began his professional life as a zoologist. After taking his bachelor’s degree at Cornell University in 1933 and his Ph.D. at the University of Rochester in 1938 under Professor Willier, he worked in Cambridge, Mass., and in Wyoming. His first publish~ papers concern the structure and function of the pituitary gland of birds, snakes and lizards; this was followed by work on the placenta and corpus luteum in viviparous snakes. Then came the move to Dr. Wallace 0. Fenn’s laboratory at Rochester, N.Y., in 1941. The sparks from three fine minds - Fenn, Otis and Rahn - and the pressure of the war effort, resulted in a revolution in the study of basic respiratory physiology. As noted by Dr. Fenn in the preface to the well-known Air Force Technical Report of 1951, three concepts guided the thinking of this group: “. . . the pressure-volume diagram of the chest and lungs . . . the oxygen-carbon dioxide diagram of the comratio of the alveoli”. position of the alveolar air . . . and the ventilation-~rfusion Problems of atelectasis, gas exchange and arterial oxygenation during acclimatization to high altitude, relation between ventilation and perfusion and the role of their maldistribution in alveolar gas exchange, body gas stores, analysis of mechanics of breathing still forming the cornerstone of today’s knowledge in this field, and many others were first successfully tackled in this period. In 1956, Dr. Rahn accepted the chair of Physiology at the School of Medicine of the University of Buffalo; in 1973 he was appointed Distinguished Professor of 3
4
FOREWORD
Physiology at the State University of New York at Buffalo. Here, approaches and methods previously developed were extended and are being applied to a wide range of questions of comparative physiology. A main area of personal interest is that of gas exchange in water breathers uersus air breathers, and the consequences of the transition from water- to air-breathing. Hermann Rahn beautifully demonstrated on theoretical and experimental grounds that water-breathers must have a much lower carbon dioxide tension in their blood than air-breathers, but that their blood pH is about the same, thanks to adaptation of the bicarbonate concentration. A second area of investigation results from the observation that the blood pH of invertebrates and vertebrate ectotherms is critically influenced by thermal changes, but that the difference between blood pH and neutral (water) pH does not change. From this remarkable phenomenon Hermann Rahn forged the concept of constant relative alkalinity, a concept which has inspired many research groups all over the world. A third subject of interest is embryonic development of birds and the gas exchange across the egg shell and its membranes at low and high altitudes and for different sizes of birds. Among other things, Hermann Rahn has shown how the bird, starting from a single cell, the egg, equilibrated with ambient air, progressively builds up its gas exchange through shell pores of a size appropriate to the energy-metabolism intensity and the atmospheric pressure, to permit the simultaneous adequate diffusion of oxygen, carbon dioxide and water vapor. Teaching has always been inseparable from experiment for Hermann Rahn. On the podium before a large class, in the seminar room, or at the lab bench, he is an inspiring master. The gift of transmitting knowledge to the young student, and of making the more advanced think through his experiment, is not given to all; by lecture, discussion and by example, Dr. Rahn has aided hundreds to reason competently. Dr. Rahn has devoted much time to serving his University, the community, and national and international needs. Study sections, special committees on goals at the Natictnal Institutes of Health; evaluation committees for the National Aeronautics and Space Administration and the Air Force, and many others, have caused him to travel often in recent years. His influence on physiological publication has been notable: as a member of the Editorial Board and first Section Editor for Respiration, he has long been associated with the American Journal of Physiology and the Journal of Applied Physiology; he was co-editor of the relevant Handbook of Physiology series ; and was also a godfather to this journal at its inception ten years ago. Dr. Rahn has long worked for international exchange in matters ofphysiology, not only through sponsorship of foreign Fellows, but also through the Executive Committee of the International Union of Physiological Sciences, in the organization of international meetings and Congresses of Physiology. Hermann Rahn’s accomplishments have been recognized by many learned societies. He holds honorary degrees from the University of Paris (1964), and the Univer-
FOREWORD
5
sity of Yongsei (1965), and his own alma mater, the University of Rochester (1975). Member of the National Academy of Sciences in the United States, and a charter member of that country’s Institute of Medicine, he is also past president of the American Physiological Society and a recipient of the Al Behnke Award (1973) for his contributions to undersea biology. Respiration Physiology is indeed proud to dedicate this issue to Hermann Rahn, eminent scholar, inspiring teacher and conscientious promotor of international exchange among scientists. Pierre Dejours and Leon Farhi
FOREWORD
This issue of ~~~~~~~ti~~P~ys~~~~gyis dedicated to Hermann Rahn, imaginative investigator, teacher and mentor, friendly but incisive critic, physiologist par exceilence. The articles were written by some of the collaborators, and by students privileged to have worked with Dr. Rahn, an opportunity that was usually decisive for their careers. His encouragement - and his ideas - were of crucial importance in directing the authors’ early work, and his outstanding qualities have left a lasting mark on all those who benefited from his direction. Dr. Rahn’s broad interests cannot be adequately reflected in any one specialty journal, but since the field of respiratory physiology will forever bear his imprint, it is appropriate to honor him in these pages. Born in East Lansing, Michigan, in 1912, Dr. Rahn grew up in a family of nature lovers. His father, an eminent bacteriologist, early introduced him to the value of careful observation and the joys of collecting, habits evident today to anyone walking or driving with Dr. Rahn for half an hour in the countryside. Seeing the remarkable in nature, and following up with the right questions, form the basis of the extraordinary, often colorful variety of physiological problems he later examined. Hermann Rahn began his professional life as a zoologist. After taking his bachelor’s degree at Cornell University in 1933 and his Ph.D. at the University of Rochester in 1938 under Professor Willier, he worked in Cambridge, Mass., and in Wyoming. His first publish~ papers concern the structure and function of the pituitary gland of birds, snakes and lizards; this was followed by work on the placenta and corpus luteum in viviparous snakes. Then came the move to Dr. Wallace 0. Fenn’s laboratory at Rochester, N.Y., in 1941. The sparks from three fine minds - Fenn, Otis and Rahn - and the pressure of the war effort, resulted in a revolution in the study of basic respiratory physiology. As noted by Dr. Fenn in the preface to the well-known Air Force Technical Report of 1951, three concepts guided the thinking of this group: “. . . the pressure-volume diagram of the chest and lungs . . . the oxygen-carbon dioxide diagram of the comratio of the alveoli”. position of the alveolar air . . . and the ventilation-~rfusion Problems of atelectasis, gas exchange and arterial oxygenation during acclimatization to high altitude, relation between ventilation and perfusion and the role of their maldistribution in alveolar gas exchange, body gas stores, analysis of mechanics of breathing still forming the cornerstone of today’s knowledge in this field, and many others were first successfully tackled in this period. In 1956, Dr. Rahn accepted the chair of Physiology at the School of Medicine of the University of Buffalo; in 1973 he was appointed Distinguished Professor of 3
4
FOREWORD
Physiology at the State University of New York at Buffalo. Here, approaches and methods previously developed were extended and are being applied to a wide range of questions of comparative physiology. A main area of personal interest is that of gas exchange in water breathers uersus air breathers, and the consequences of the transition from water- to air-breathing. Hermann Rahn beautifully demonstrated on theoretical and experimental grounds that water-breathers must have a much lower carbon dioxide tension in their blood than air-breathers, but that their blood pH is about the same, thanks to adaptation of the bicarbonate concentration. A second area of investigation results from the observation that the blood pH of invertebrates and vertebrate ectotherms is critically influenced by thermal changes, but that the difference between blood pH and neutral (water) pH does not change. From this remarkable phenomenon Hermann Rahn forged the concept of constant relative alkalinity, a concept which has inspired many research groups all over the world. A third subject of interest is embryonic development of birds and the gas exchange across the egg shell and its membranes at low and high altitudes and for different sizes of birds. Among other things, Hermann Rahn has shown how the bird, starting from a single cell, the egg, equilibrated with ambient air, progressively builds up its gas exchange through shell pores of a size appropriate to the energy-metabolism intensity and the atmospheric pressure, to permit the simultaneous adequate diffusion of oxygen, carbon dioxide and water vapor. Teaching has always been inseparable from experiment for Hermann Rahn. On the podium before a large class, in the seminar room, or at the lab bench, he is an inspiring master. The gift of transmitting knowledge to the young student, and of making the more advanced think through his experiment, is not given to all; by lecture, discussion and by example, Dr. Rahn has aided hundreds to reason competently. Dr. Rahn has devoted much time to serving his University, the community, and national and international needs. Study sections, special committees on goals at the Natictnal Institutes of Health; evaluation committees for the National Aeronautics and Space Administration and the Air Force, and many others, have caused him to travel often in recent years. His influence on physiological publication has been notable: as a member of the Editorial Board and first Section Editor for Respiration, he has long been associated with the American Journal of Physiology and the Journal of Applied Physiology; he was co-editor of the relevant Handbook of Physiology series ; and was also a godfather to this journal at its inception ten years ago. Dr. Rahn has long worked for international exchange in matters ofphysiology, not only through sponsorship of foreign Fellows, but also through the Executive Committee of the International Union of Physiological Sciences, in the organization of international meetings and Congresses of Physiology. Hermann Rahn’s accomplishments have been recognized by many learned societies. He holds honorary degrees from the University of Paris (1964), and the Univer-
FOREWORD
5
sity of Yongsei (1965), and his own alma mater, the University of Rochester (1975). Member of the National Academy of Sciences in the United States, and a charter member of that country’s Institute of Medicine, he is also past president of the American Physiological Society and a recipient of the Al Behnke Award (1973) for his contributions to undersea biology. Respiration Physiology is indeed proud to dedicate this issue to Hermann Rahn, eminent scholar, inspiring teacher and conscientious promotor of international exchange among scientists. Pierre Dejours and Leon Farhi
