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Biographical Memoirs: Volume 69 (1996)

Chapter: HERMANN RAHN

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Suggested Citation:"HERMANN RAHN." National Academy of Sciences. 1996. Biographical Memoirs: Volume 69. Washington, DC: The National Academies Press. doi: 10.17226/5193.
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H E RMANN RAH N July 5, 1912-June 23, 1990 BY iOHN PAPPENHEIMER I do not wish to be a professor and just sit and count the veins of a butter- fly (wing) and then try to determine their names. I could not stand that for long. I am more interested in the whole animal world.... My ideal is not a professor but a man like Ernest Thomson Seton. . . by reading his books I try to learn how to live in the woods, how one can sleep warm there in the winter at below freezing temperatures, what wood burns best, how to make a fire in the rain, what provisions one takes on a long trip when you are all alone. SO WROTE THE SIXTEEN-YEAR-QED Hermann Rahn to his clos- est frienc! en c! schoolmate, Wolf Tischier, in Germany. Despite these youthful sentiments, Hermann clic! become a professor en c! one of the foremost physiologists of his gen- eration. Only a few years later, while still a student, he again wrote to his friend, Wolf, this time saying: Natural History is not the problem of today, it is merely a good and inter- esting basis. I believe that experimental zoology with its "cause and effects" has gotten hold of me.... I was torn between two worlds. Both afford interesting problems, but I never found a connection between them. You work either systemically and anatomically or on the other hand as physiolo- gist and experimental zoologist. According to my mind the latter offers the greater problems.... After being torn between these two worlds it is a good feeling at last to know my way. These were serious thoughts for a schoolboy, en c! they 243

244 B I O G RA P H I C A L EMOIRS reveal Hermann's commitment to research in biology at an early age. In the enc! he fount! the connection between the two worIcis, en c! incleec! his abiding love of natural history en c! the call of the wiTc! cleterminec! the course of much of his experimental work on respiratory en c! comparative physi- ology. Hermann was brought up in an academic milieu. His father, Otto Rahn, was professor of bacteriology en c! dairy chemistry, first at Kiel in Germany en c! later at Cornell University in Ithaca, New York. His mother knee Bell FarrancI, ISS3) was a fourth-generation native of Lansing, Michigan, en c! she was Otto's research assistant at the Agricultural College in Lansing prior to their marriage. Hermann was the elclest of their four chilciren, en c! most of his formative years were spent in a happy, stable, and intellectually stimu- lating family environment in Kiel, Germany, en c! Ithaca, New York. Nevertheless, the first few years of his life were unusually turbulent, no account of his life wouIc! be com- plete without providing brief biographies of his parents and the history of their early marries! life. Otto Rahn was one of eleven chilciren born to uneclu- catec! Mennonite parents in the little town of Tiegenshof in East Prussia. He was a star student at the town school, and, with the sympathetic support of his father and his math- ematics teacher, he was able to attenc! the University of Gottingen, where he stucliec! physical chemistry with W. Nernst en c! organic chemistry with Professor WalIach (later to become Nobel laureate in chemistry). Otto obtainer! his Ph.D. in 1902 at the age of twenty-one, but academic positions in chemistry were scarce, en c! he acceptec! a position in the Department of Dairy Science. His acivancec! training in organic chemistry en c! mathemat- ics was unusual in this fielcI, en c! he soon fount! applica- tions to bacterial metabolism that brought him international

HERMANN RAHN 245 renown. In 1906 he was offerer! a faculty position in bacte- riology at Michigan State and 1907 found him struggling with the English language while teaching chemistry en c! bacteriology to students in the agricultural college at Lan- slng. In the same year, Bell Farranc! (Hermann's mother-to- be) gracluatec! from Michigan State en c! acceptec! a job as assistant to Professor Clinton Dewitt Smith, who was about to become president of a small agricultural college in Perchicaba, Brazil, six-hours travel west of San PauTo. That was an extraordinary adventure for a well-brought-up young lady from Michigan in 1907, but in her own words, "My nature has always been a bit on the romantic sicle en c! hav- ing a young en c! adventurous heart I just conic! not turn clown such an offer to see the worIcI, even though I clic! not like Mr. Smith." Her romantic nature was to be transmitter! en c! amplifier! in her son Hermann, whose interests in envi- ronmental and comparative physiology led him to roam the woricI. Bell returnee! to Lansing in 1908 to join the Depart- ment of Bacteriology uncler Professor Marshall, but she was soon assignee! to Otto Rahn as a research en c! teaching assistant. They were marries! in 1911, en c! Hermann was born on July 5, 1912. Two years later the Rahns boarclec! a ship for Germany so that Bell could meet Otto's family and show off their two- year-oIc! Hermann to relatives. The Archduke Ferclinanc! was assassinates! while they were on the high seas, en c! WorIc! War I began shortly after they clisembarkoc! in Hamburg. Although Otto was in the process of becoming a U.S. citizen, he en c! his American bricle were cIassifiec! in Ger- many as German citizens, en c! they were not permitted to return to the Uniter! States even though Bell was six months pregnant and anxious to return home. Hermann's sister, Marie, was born in November 1914, en c! soon thereafter

246 B I O G RA P H I C A L EMOIRS Otto was ciraftec! into the army en c! assignee! menial acimin- istrative jobs at a small airfield! in Latvia. One of Otto's sisters owner! a bookstore in Danzig, en c! Bell, Hermann, en c! the baby mover! into a room over the store. For the next four years Bell was cut off from commu- nication with her own family in Michigan, en c! it was not until November 1918 that she learner! through the Norwe- gian Rec! Cross of her mother's cleath. Hermann, by then six years oIcI, hac! no shoes en c! froze his toes while waiting in line for the tinily family ration of ~ pint of skimmer! milk. Bell's footwear was reclucec! to her satin wocicling slip- pers until Otto manager! to provide her with a pair of sec- oncI-hanc! army boots he hac! traclec! for his tobacco rations. After the war anti-German feelings remainec! high in the Uniter! States, en c! since Otto hac! servec! in the German army he was not invites! to return to Michigan. At the same time, German universities were in disarray, en c! it was not until 1920 that he obtainer! a suitable post as professor of ciairy physics at Kiel. Hermann was then eight years oicI, en c! so his early schooling began in Germany. At this time, also, he en c! his frienc! TischIer (later to become professor of ecology at Kiel) began collecting en c! identifying butter- flies, insects, bircis, en c! fauna from the beaches of the Bal tic Sea. In 1923 his parents were able to transfer Hermann's savings account of $19.00 from America to Kiel, where in- flation was such that they were able to buy him a micro- scope and a camera, "hoping he would someday become a scientist." In 1925 W. A. Noyes, professor of chemistry at Illinois (and a member of the National Academy of Sciences), made a goodwill tour of German universities, and he became in- terested in Otto Rahn's work on the physical properties of milk products, noting that no comparable department of dairy physics existed in the United States. Unbeknownst to

HERMANN RAHN 247 her husband, Mrs. (Bell) Rahn conficlec! to Noyes that she yearner! to return home to visit her family en c! asker! whether it might be possible for him to arrange a lecture tour for her husband. This iclea bore fruit, en c! in 1926 the entire Rahn family visitor! America, the chilciren learning English from their American cousins while Professor Rahn went coast to coast on his lecture tour. Shortly after returning to Kie! he receiver! an offer to come to Cornell University as ten- urec! professor of bacteriology en c! dairy physics. Hermann was enrollee! in the local high school in Ithaca en c! starter! his transition to the American eclucational system en c! way of life. The wilclerness of the Finger Lake district of upper New York state was in contrast to the manicures! country arounc! Kiel, en c! Hermann was fascinates! by it. Through- out his school en c! unclergracluate years at Cornell he spent many clays en c! sometimes weeks camping out in the wiTcis, collecting or identifying the flora en c! fauna. During the summers he took jobs as nature counselor at a Boy Scout camp or as assistant in government fisheries or wiTcIlife cle- partments. At college he grounclec! himself in the chemical en c! physical sciences neeclec! for his planner! career in ex- perimental zoology. After graduating from Cornell in 1933, Hermann returnee! to Kiel for one year before enrolling as a graduate student en c! teaching assistant in zoology at the University of Rochester. His roots in Germany were creep, en c! he was torn between Germany en c! the Uniter! States. It was not until 1936, after a seconc! visit to Kiel, that he was able to write to his frienc! Wolf, ". . . America has at last become my real home." CONTRIBUTIONS TO REPRODUCTIVE PHYSIOLOGY OF SNAKES AND BIRDS, 1937-43 Hermann's first publications, based on his independent work as a graduate student, were concernec! with the repro

248 B I O G RA P H I C A L EMOIRS cluctive physiology of viviparous snakes en c! on the clevelop- ment of the pituitary glanc! in bircis. His discovery in 1937 that viviparous snakes develop a primitive placenta analo- gous to the mammalian organ won him a National Research Council postcloctoral fellowship to work in reproductive physiology with Frederick Hisaw at the Harvarc! Biological Laboratories. His year at Harvarc! (1938-39) was eviclently a productive one for it lee! to a series of eight papers on the structure en c! function of the pituitary in bircis en c! snakes. With Louis Kleinho~z he clevelopec! a biological assay for the melanophore-stimulating hormone ("intermeclin") of the pars intermeclia en c! cleterminec! its activity in a variety of mammalian species. At the same time, he completec! a cletailec! histological stucly of cell types in the pars anterior of eighteen species of bircis en c! shower! that all these spe- cies lackey! an intermediate lobe. In the same year he fount! that female garter snakes, collectec! from Penekese Islanc! off Cape CocI, conic! store viable sperm in utero for at least one month following insemination, so that the exact time of fertilization of ova and the gestation period were inde- terminate. Finally, he fount! time to court en c! marry Katherine (Kay) Wilson, a student at the Graduate School of Landscape Architecture. In September 1939 Hermann mover! to his first academic post as instructor in zoology at the University of Wyoming at Laramie. There he macle goof! use of the mountains en c! prairies to combine his love of nature en c! natural history with his interests in the reproductive behavior of reptiles. He fount! that rattlesnakes living at an altitucle of 6,000 feet, where the summers are short, have a two-year repro- ductive cycle, a phenomenon made possible by storage of viable sperm over the winter in a special pocket of the uterus. During the winter hibernation period, also, mature ova were retainer! in the ovaries en c! not clischargec! to meet

HERMANN RAHN 249 the sperm until spring. This bizarre schecluTe meant that at any one time cluring the summer approximately 50 percent of the aclult females were gravicI. At lower altitucles, where the summers are longer en c! warmer, the same species of rattler has a one-year reproductive cycle, en c! almost all the aclult females are gravicI. Rahn's principal paper describing this work (publisher! in Copeia, 1942) is as convincing as it is interesting, en c! the simple but original style of this early publication foreshadowed the elegant simplicity of exposi- tion for which he later became noted. His sojourns on the prairies also lee! him to stucly reproductive behavior en c! sexual dimorphism of the sage grouse, when Hermann spoke of the elaborate courtship ciances of these bircis, you lis- tenec! to sheer poetry. PULMONARY MECHANICS AND BLOOD-GAS EXCHANGE; YEARS WITH WALLACE FENN, 1941-56 WorIc! War II en c! chance events abruptly alterec! the course of Rahn's career en c! the direction of his research. Of the chance events, uncloubtecIly the most important was his meeting with Wallace Fenn in Rochester in the summer of 1941. This meeting occurrec! when Hermann, coming east from Wyoming for a visit to his parents, stopper! briefly in Rochester to visit friends before proceeding to Ithaca. He caller! on Fenn, whom he greatly acimirecI, en c! before their conversation was over Fenn offered him a job as instructor in physiology, an offer that was acceptec! on the spot. Fenn was already one of the most distinguished general physiolo- gists in the country, having macle pioneer contributions to the mechanism of phagocytosis, the heat production of con- tracting muscle, the metabolism of active nerve, en c! the exchange of electrolytes in excitable tissues.1 Hermann was to become Fenn's closest colleague, confidant, and scien- tific protege. Shortly after the United States entered World

250 B I O G RA P H I C A L EMOIRS War II, the National Research Council asker! Fenn to inves- tigate the possibility that the operational altitucle of Air Force personnel might be increasec! by breathing oxygen uncler pressure (positive pressure breathing). Neither Fenn nor his junior colleagues hac! ever worker! in the field! of human respiration, but they acceptec! the challenge en c! in the perioc! ~941-45 clevelopec! funciamental new approaches to pulmonary mechanics en c! respiratory gas exchange- concepts that helpec! to introduce a goIclen age of theoreti- cal and applied respiratory physiology in the decade follow- ing WorIc! War II. In this clevelopment, Hermann Rahn playact a central role, although his association with Fenn en c! other colleagues was so close that it is clifficult for a biographer to separate the relative contributions macle by each incli- viclual. It is reasonable to suppose, however, that Fenn's quantitative biophysical approach awakened latent talents in Hermann Rahn that macle him a full partner in the enterprise en c! shaper! his own approach to biological prob- lems cluring the next forty years. Two major contributions to respiratory physiology emerged from the 1941-45 work on positive pressure breathing by the Rochester team, en c! both were publisher! in 1946 in the American Journal of Physiology. The first was titles! "The Pressure-Volume Diagram of the Thorax en c! Lung" with Rahn as senior author, the seconc! was "A Theoretical Stucly of the Composition of Alveolar Air at Altitude" with Fenn as senior author. The first paper became the starting point for research on pulmonary mechanics in many physiologi- cal en c! clinical laboratories. The seconc! paper proviclec! a graphical solution to equations describing the partial pres- sures of oxygen en c! carbon clioxicle in alveolar gas as a function of barometric pressure (altitucle), inspirer! gas com- position, en c! respiratory exchange ratio. While most of the equations underlying this analysis had been derived inde

HERMANN RAHN 251 penclently by others, their representation in a graphical form that conic! easily be unclerstooc! en c! applier! to a variety of problems was a major contribution comparable to the cIas- sic nomographic analysis of blooc! chemistry by L. l. Henclerson.2 IncleecI, the next important step was to extent! the analysis to the bloocI-gas exchange, en c! in 1949 Rahn published his now classic paper titled "A Concept of Mean Alveolar Air en c! the Ventilation-Blooc! Flow Relationships During Pulmonary Gas Exchange." In this paper Rahn shower! how regional differences in the ratio of alveolar ventilation to alveolar blooc! perfusion (VA/Q) give rise to oxygen pres- sure differences between mean alveolar gas en c! blooc! leav- ing the lungs. His analysis was presented in a clear graphi- cal form that has been user! by many subsequent investigators. At the time of this work, there were no experimental meth- ocis for determining regional pulmonary blooc! flow or ven- tilation, en c! Rahn hac! to assume normal Gaussian clistribu- tions in order to provicle numerical solutions in graphical form. More than ten years later, when methods for cleter- mining regional ventilation en c! perfusion using raclioac- tive gases hac! been clevelopec! by I. B. West3 en c! others, it was fount! that the distribution of VA/Q was far from Gaussian. Nevertheless, the new experimental ciata were easily incor- poratec! into Rahn's theoretical analysis, which continues to be the preferred means of presenting the data. Abnor- malities of VA/Q, rather than diffusion capacity, prover! to be the most common cause of poor oxygenation of arterial blooc! in a variety of pulmonary diseases, en c! Rahn's analy- sis provides the theoretical basis for clinical tests of im- paired gas exchange. The techniques en c! concepts clevelopec! to investigate respiratory gas exchange during acute exposure to low baro- metric pressures (altitucle) were well suites! to studies of other perturbations of the respiratory environment, includ

252 B I O G RA P H I C A L EMOIRS ing the inhalation of CO2, hyperventilation, breath-hoicI- ing, cliving, en c! acclimatization to altitucle. All of these per- turbations were stucliec! by the Rochester team, but for Rahn the lure of the mountains was not to be cleniecI, en c! cluring the immediate postwar years he organizer! three expecli- tions to high altitucles in Wyoming, Coloraclo, en c! the Pe- ruvian Ancles. He en c! his colleagues were first to show that respiratory acclimatization ant! cleacclimatization to altitucle, measurer! in terms of alveolar gas composition, occurs ex- ponentially with a half-time of about twelve hours. The re- sults were clearly clelineatec! as a hysteresis loop on the Fenn-Rahn O2-CO2 diagram, en c! they proviclec! the starting point for subsequent studies by Severinghaus4 en c! others showing that the time course of acclimatization is cleter- minec! by changes in composition of cerebral fluicis bathing meclullary chemoreceptors. BLOOD-GAS EXCHANGE AT HIGH AND LOW PRESSURES; PHYSIOLOGY OF DIVING IN THE AMA (DIVING WOMEN) OF KOREA AND JAPAN, 1956-68 In 1956 Rahn mover! to the University of Buffalo Meclical School as chairman of the Department of Physiology en c! with him mover! the center of gravity of the Rochester school of respiratory physiology. In the years to come he was to attract more than 100 collaborators from some twelve coun- tries to work on such diverse topics as respiratory gas ex- change in cliving insects, the regulation of pH in polkilo- therms, the role of nitrogen in the absorption of gas pockets in animals en c! humans, distribution of ventilation en c! per fusion in health en c! disease, respiratory gas equations as applied to gill breathing, the physiology of diving in the Ama sea-women of Korea en c! Japan, en c! allometric studies of gas exchange through the eggshells of cleveloping birc! embryos ranging from hummingbirds to ostriches. Although

HERMANN RAHN 253 each of these topics was interesting in itself, Rahn always sought for generalities en c! for ways to present both the problem en c! its solution so clearly that even a nonspecialist conic! appreciate its interest en c! significance. For this rea- son he was invites! to give many public lectures, en c! the following examples taken from the titles of some of his lectures or essays will illustrate the point: The Unique Behavior of Nitrogen Gas Breath Hoicling in the Mountains en c! Underwater Lung Collapse en c! Our Space Missions Hydrogen Ion Regulation, Temperature, en c! Evolution The Diving Women of Korea en c! Japan How We Store Oxygen Why Fish Have Very Low Arterial CO2 Tensions How Eggs Breathe Rahn's interest in the physiology of cliving arose from his analysis of gas exchange cluring breathhoicling, en c! eventu- ally this lee! him to investigate the remarkable cliving ability of the cliving women of Korea en c! Japan. This work was catalyzer! by S. K. Hong, a Korean physiologist who came to Buffalo to study respiratory physiology with Rahn. Together they organizer! expeditions to the coasts en c! islancis of south- ern Korea and Japan, where for centuries women divers have harvestec! the sea floor for foocI, using only face masks for equipment en c! enduring high pressures en c! extreme coicI. Using a simple but ingenious crevice for collecting alveolar samples underwater, Rahn and Hong were able to chart the changes of alveolar gas composition as a function 1 of time en c! pressure cluring clives by specially trainee! na- tive slivers. Compression of the lungs cluring clives to 7 to ~ 0 meters produced correspondingly increased gas pres- sures, but, of course, oxygen was consumed, so expansion

254 BIOGRAPHICAL MEMOIRS of gases during ascent to the surface caused rapid decrease of oxygen pressure to astonishingly low values so low in fact that blood entering the lungs lost oxygen to the gas phase and imperilled consciousness. Detailed quantitative explanation of this reversal and the critical conditions for surviving free dives were subsequently worked out in the home laboratories in Buffalo en c! Seoul, and in subsequent years, also, the physiological adaptations of these hardy women to extreme cold were investigated. A popular ac- count of this work was presenter} by Rahn and Hong in a Scientific Amera can article (19671. Several of the young Ko- rean medical doctors enlisted to help with this project were stimulated to choose physiology as a career, and indeed this collaborative enterprise introduced modern respiratory physi- ology to both Korea and Japan. This was a special satisfac- tion to Rahn, who was awarded an honorary LL.D. degree from Yonsei University in 1965. At this stage of his scientific career, Rahn's important contributions to respiratory physi- ology were also recognized by his election to the American Academy of Arts and Sciences, the presidency of the Ameri- can Physiological Society, and in 1968 to the National Acad- emy of Sciences. GAS EXCHANGE IN AVIAN EGGS AND ITS ROLE IN EMBRYONIC DEVELOPMENT, 1968-90 * In 1968 Rahn started a completely new venture, namely the respiratory physiology of avian eggs and embryos. This project was to be the principal focus of his research until his death in 1990 and to it he brought an unprecedented knowledge of respiratory gas exchange combined with his lifelong enthusiasm for field studies in classical zoology. In the preface to his two-volume collection of papers in this field he remarks, "The beginning of our interest in gas exchange of Ivan eggs can be clearly documented. It oc

HERMANN RAHN 255 currec! in 1968 after the arrival of Douglas Wangensteen as a Postcloctoral Fellow.... One clay he asker! us how eggs breathe. Since none of us hac! even thought about this prob- lem, we suggestec! that he might fins! out." Wangensteen en c! Rahn soon cleterminec! that exchange of oxygen, CO2, and water vapor occurs principally by simple passive diffu- sion through pores in the shell, en c! this raiser! a host of basic questions. If gas exchange is limiter! by diffusion through the shell, how clo gas pressures in the tissues change as the embryo increases in size en c! metabolism cluring incuba- tion? What determines the number, diameter, length, en c! total area of the pores in the shell? How are pore climen- sions acljustec! to provicle sufficient conductance for respi- ratory gases but without fatal loss of water vapor? What are the relations between pore area, thickness of shell, en c! gas conductance as a function of egg sizes from ~ gram (wrens) to 1,500 grams (ostriches)? How cloes porosity of eggs at high altitucle compare with those of the same size at sea level? Can bircis from sea level adjust the porosity of their eggs to compensate for changer! cliffusivity en c! oxygen pres- sures at altitucle? The answers to almost all these questions and many more were described in some seventy publica- tions with more than fifty collaborators from arounc! the worIcI. The answers involves! measurements of gas exchange on fresh fertile eggs from some 100 species of bircis nesting in locations from Spitsbergen to remote islancis of the South Pacific, from the deserts of Israel to the Himalayas, from Alaska to the nesting mounds of wiTc! turkeys in Australia. Two illustrations (Figures ~ en c! 2) from a Scientific Ameri- can article titled "How Birds Breathe" by Rahn, Ar, and Paganelli (1979) are reproduced in this memoir because they exemplify the generality of Rahn's thinking and the elegant simplicity of his expository skill. Rahn's last paper, published posthumously, was on a noninvasive recording of

256 100 In .( 10 C, - o 1= o m c' 1.0 1 L ~ ......... ~- -~. ./ CATBIRD-/. ·' ..,y ·~' it\ HOUSE WREN _N B I O G RA P H I C A L EMOIRS LAYSAN ,/ ` ALBATROSS ~ /1,: i.~....& .~h ~GOLDEN\ / / ~;-~x ~ ~< PUFFIN ~ WANDERING EAGLE' - ~ _-- ~ 1'l- -->,~f ADELIE PENGUIN /^ \ CHICKEN ~ - ~ -. i^ SHEARWATER ~ ~\ ~ ; SOOTY TERN ~ ,~e - ''ARCTIC TERN ~ _ / /\LEAST TERN it' .~ ALBATRORR , ~(\ i,.. 1 10 100 1,000 EGG MASS (GRAMS) Figure 1 Loss of water during incubation is independent of the metabolic rate of the embryo, yet it appears to be essential for suc- cessful hatching. Here the total amount of water lost during incuba- tion has been plotted against the initial mass of the egg. The graph includes data obtained from sixty-five species of eggs ranging in size from 1 gram to 500 grams, with incubation times ranging from eleven to seventy days. There is a remarkably consistent trend: regardless of egg mass or incubation time, the typical egg will lose 15 percent of initial mass during natural incubation.

HERMANN RAHN - ~ 100 Lo ~ 10 In CE J J - 1 UJ an o .1 as lo o .01 ~100 OXYGEN CONDUCTANCE 1- ~, |~-WITH . 1 1 1 1 1 0 1 00 1 ,000 EGG MASS (GRAMS) 257 In 10 ~ 111 3 I CD I J llJ o .1 .01 Figure 2 Pore length and oxygen conductance increase at different rates with increasing egg mass, as is shown in this graph encompass- ing data from the eggs of some ninety species from different parts of the world. For every tenfold increase in mass, the oxygen conduc- tance of the eggshell increases 6.5 times, but the pore length in- creases only 2.7 times. Pore length probably increases slower be- cause the eggshell must be thin enough for the embryo to hatch. the heartbeat of developing bird embryos by means of a microphone placer! in a sealer! chamber containing the egg. SERVICE TO SCIENCE: NATIONAL AND INTERNATIONAL Rahn was a member of numerous scientific societies, en c! he received distinguished service awards from several of them. However, his primary allegiance was to the American Physiological Society (APS) en c! to the International Union of Physiological Sciences (IUPS). He was president of APS

258 B I O G RA P H I C A L EMOIRS (1963-64) and served for many years as scientific editor and boars! member of its publications, inclucling the compre- hensive en c! scholarly two-volume Handbook of Respiratory Physiology, which crownec! more than a clecacle of major acI- vances in this fielcI. He also gave generously of his time to advisory panels of the National Research Council, the Na- tional Institutes of Health, the National Aeronautics en c! Space Administration, en c! the American Institute of Bio- logical Sciences. Travel en c! international aspects of physiology playact a major role in Rahn's life. His roots in Europe, his colIabo- rative research with physiologists from many countries, en c! his sensitivity to different cultures gave him a strong voice in the International Union of Physiological Sciences. He server! on its council from 1965 to 1971 en c! subsequently as its vice-presiclent. From Wallace Fenn he absorber! a strong tradition of loyalty to the triennial international congresses of physiology, en c! he server! on the executive committee of the large en c! successful XXIVth Congress hell! in Washing- ton, D.C., in 1968. On several occasions he server! as resi- clent visiting professor at foreign universities. TEACHER, SCHOLAR, AND GENTLEMAN Rahn grew up in a prewar academic environment in which research was regarclec! as a joyous, spare-time privilege of a university teacher rather than a ciriving professional career. This point of view changer! rapicIly after the war, when large- scaTe government support for research macle it possible for young scientists to create incliviclual research empires with- out regarc! for teaching or other traclitional academic re- sponsibilities. Rahn was especially vulnerable to this devel- opment because his research on gas exchange at high en c! low barometric pressures had important applications to both clinical and military problems. He was well supported by

HERMANN RAHN 259 contracts from the Air Force en c! the Office of Naval Re- search as well as from the National Science Foundation en c! the National Institutes of Health, it wouIc! have been easy for him to neglect his teaching en c! university responsibili- ties, but to this temptation he never succumbed. Instead, he remained true to his principles, namely, that the pri- mary responsibility of university professors is to their stu- clents en c! departments. At the time he mover! to Buffalo in 1956, he organizer! a comprehensive course in human physi- ology for meclical students, en c! he continues! to play a ma- jor role in teaching it throughout his tenure as heat! of the department. At the same time, he createc! a stimulating research environment for all members of his staff as well as for the continual stream of postcloctoral fellows, many from abroad, who came to work with him. He was a magnetic source of icleas, drawing in all those arounc! him, en c! over the years he colIaboratec! en c! publisher! with all fourteen of his permanent staff members. As one staff member put it, "tRahn] hac! a way of sharing his excitement over a new iclea en c! before you knew it both of you were in the lab trying it out." Hermann Rahn was equally at home in the wiTclerness en c! in the most formal settings. In civilizer! society he usu- ally ciressec! impeccably, en c! his innate courtesy, modesty, and sensitivity to others (perhaps best described as "courtTi- ness") allowed him to fit in with all social situations, how- ever foreign or sophisticated. His concern for others en c! his willingness to take on responsibility enclearec! him to all those who hac! the privilege of working with him. I have a vivic! memory of an exhaustec! Hermann after he hostel! a three-day meeting of 800 members of the American Physi- ological Society in Buffalo, he was walking back to the lab with drooping shoulders, laden with shopping bags full of

260 B I O G RA P H I C A L EMOIRS presents for the secretaries en c! others who hac! helpec! him organize the meeting. In 1973 Rahn retiree! as chairman of the department en c! became distinguished service professor of physiology. The International renown he brought to this university was fur- ther recognizec! by various awards, including the Stockton Kimball Awarc! in 1969 en c! the Chancellor Norton Mecial in 1981. In 1985 the experimental cliving laboratory that hac! been constructor! by the Office of Naval Research for Rahn's studies of underwater physiology was renames! "The Hermann Rahn Laboratory of Environmental Physiology." In the spring of 1990 Rahn learner! that he hac! incur- able pancreatic cancer, but he continues! to work in the lab as long as physically possible, en c! he was working on a manuscript in bee! at home a few clays before the anti. In one of his last letters to his lifelong frienc! Wolf Tischier he commented! on his life: . . . the general maturing of a happy child with his insect collecting, his love with all nature, his wonders and aspirations . . . to the mature student, the young investigator and finally the reflecting scientist . . . I am happy to have stayed a romantic in science. Today my colleagues have become busi- ness scientists and I am sure your colleagues have to do the same in order to survive as researchers. So we have both been most fortunate because we are both in a sense still children, with our youthful enthusiasm to explore and search for answers. ACKNOWLEDGMENTS ARE DUE PROFESSOR Wolfgang Tischler for reading the manuscript of this memoir and for giving permission to quote from his correspondence with Hermann; Hermann's sister, Marie Wohlmann, and his son, Robert, for allowing me to read and quote from the typewritten autobiographies left to them by Otto and Bell Rahn; and members of Rahn's staff at Buffalo, especially Charles Paganelli, R. Blake Reeves, and Augusta Dustan for their comments.

HERMANN RAHN NOTES 261 1. See "Wallace O. Penn," in Biographical Memoirs, vol. 50, pp. 141-73. Washington, D.C.: National Academy of Sciences, 1979. 2. L. T. Henderson. Blood: A Study in General Physiology. New Ha- ven, Conn.: Yale University Press, 1928. 3. T. B. West. British Medical Bulletin, 19~1963~:53-60. 4. T. W. Severinghaus, et al. Journal of Applied Physiology, 18~1963~:1155 56.

262 S E L E C T E D 1938-39 1960 1963-64 1964 1965 1966 1968 1971 1971-74 1973 1977 1980 1981 1981 1985 B I O G RA P H I C A L EMOIRS AWARDS AND DISTINCTIONS National Research Council fellow Harvey Society lecturer President, American Physiological Society Doctor of medicine, Honoris Causa, University of Paris Honorary LL.D., Yonsei University, Seoul American Academy of Arts and Sciences National Academy of Sciences Institute of Medicine Vice-president, International Union of Physiological Sciences Albert Behnke Award, Undersea Medical Society Honorary D.Sc., University of Rochester Distinguished professor, State University of New York at Buffalo 1976-77 Alexander von Humboldt Award and visiting professor, University of Gottingen Painton Award, Cooper Ornithological Society Profesor honoraria, Universidad Peruana, Lima Doctor of medicine, Honoris Causa, University of Berne Elliott Cones Award, American Ornithological Union Chancellor Norton Medal, State University of New York at Buffalo Dedication of the Hermann Rahn Laboratory for Environmental Physiology, State University of New York at Buffalo

HERMANN RAHN SELECTED BIBLIOGRAPHY 1939 263 Structure and function of placenta and corpus luteum in viviparous snakes. Proc. Soc. Exp. Biol. Med. 40:381-82. With L. H. Kleinholz. The distribution of intermedin in the pars anterior of the chicken pituitary. Proc. Natl. A cad. Sci. U.S.A. 25:145- 47. 1940 Sperm viability in the uterus of the garter snake, Thamnophis. Copeia (3) :109-15. 1941 With G. A. Drager. Quantitative assay of the melanophore-dispers- ing hormone during development of the chicken pituitary. Endo- crinology 29: 725-30. 1942 With F. L. Clarke and M. D. Martin. Seasonal and sexual dimorphic variations in the so-called "air sacs" region of the Sage Grouse. Wyoming Game and Fish Dept. Bull. (2) :13-27. The reproductive cycle of the Prairie Rattler. Copeia (4~:233-40. 1946 With J. Mohney, A. B. Otis, and W. O. Fenn. A method for the continuous analysis of alveolar air. 7. Aviation Med. 17: 173-79. With A. B. Otis, L. E. Chadwick, and W. O. Fenn. The pressure- volume diagram of the thorax and lung. Am. f. Physiol. 146:207- 21. With W. O. Fenn and A. B. Otis. A theoretical study of the composi- tion of alveolar air at altitude. Am. f. Physiol. 146:637-53. 1947 With A. B. Otis. Alveolar air during simulated flights to altitude. Am. J. Physiol. 150:202-21. 1948 With A. B. Otis and W. O. Fenn. Alveolar gas changes during breath- holding. Am. f. Physiol. 152:674-86.

264 B I O G RA P H I C A L 1949 EMOIRS With A. B. Otis. Man's respiratory response during and after accli- matization to high altitude. Am. f. Physiol. 157:445-62. A concept of mean alveolar air and the ventilation-blood flow rela- tionships during pulmonary gas exchange. Am. f. Physiol. 158:21- 30. 1950 With A. B. Otis and W. O. Fenn. Mechanics of breathing in man. 7. Appl. Physiol. 2 :592-607. 1953 With R. C. Stroud, S. M. Tenney, and J. C. Mithoefer. Adaptation to high altitude: respiratory response to CO2 and O2. J. Appl. Physiol. 6: 158-62. 1955 Respiration. Ann. Rev. Physiol. 17:107-28. With L. E. Farhi. A theoretical analysis of the alveolar-arterial O2 difference with special reference to the distribution effect. 7. Appl. Physiol. 7:699-703. With W. O. Fenn. A Graphical Analysis of the Respiratory Gas Exchange. Washington, D.C.: The American Physiological Society. 1957 Gasometric method for measurement of tissue oxygen tension. Fed. Proc. 16:685-702. 1960 With E. Agostoni. Abdominal and thoracic pressures at different lung volumes. J. Appl. Physiol. 15: 1087-92. With S. K. Hong and E. Y. Ting. Lung volumes at different depths of submersion. 7. Appl. Physiol. 15:550-53. 1961 With F. J. Klocke. The arterial-alveolar inert gas (N2) difference in normal and emphysematous subjects, as indicated by analysis of urine. 7. Clin. Invest. 40:286-94. The Role of N2 Gas in Various Biological Processes with Particular

HERMANN RAHN 265 Reference to the Lung. Harvey Lecture Series 55. New York: Aca- demic Press, pp. 173-99. 1962 With T. Piiper and R. E. Canfield. Absorption of various inert gases from subcutaneous gas pockets in rats. 7. Appl. Physiol. 17:268-74. 1963 With S. K. Hong, D. H. Kang, S. H. Song, and B. S. Kang. Diving pattern, lung volumes and alveolar gas of the Korean diving women (Ama) . J. Appl. Physiol. 18:457-65. With E. H. Lanphier. Alveolar gas exchange during breath-hold diving. J. Appl. Physiol. 18:471 -77. 1964 With L. E. Farhi. Ventilation, perfusion and gas exchange the VA/ Q concept. In Handbook of Physiology: Respiration, vol. 1, ed. W. O. Fenn and H. Rahn. American Physiological Society. 1966 Aquatic gas exchange: theory. Respir. Physiol. 1:1-12. 1967 With S. K. Hong. The diving women of Korea and Tapan. Sci. Am. 216:34-43. 1968 With C. V. Paganelli. Gas exchange in gas gills of diving insects. Respir. Physiol. 5:1455-64. 1970 With J. Farber. Gas exchange between air and water and the ventila- tion pattern in the electric eel. Respir. Physiol. 9:151-61. 1971 With K. B. Rahn, B. T. Howell, C. Gans, and S. M. Tenney. Air breathing of the gar fish (Lepisosteus Ossues). Respir. Physiol. 11:46-53.

266 B I O G RA P H I C A L EMOIRS With O. D. Wangensteen and D. Wilson. Diffusion of gases across the shell of the hen's egg. Respir. Physiol. 11:16-30. With O. D. Wangensteen. Respiratory gas exchange by the avian embryo. Respir. Physiol. 11:31-45. 1972 With F. W. Baumgartner. Temperature and acid-base regulation in fish. Respir. Physiol. 14:171-82. 1973 With W. F. Garey. Arterial CO2, O2, pH and HCO3 values of ecto- therms living in the Amazon. Am. f. Physiol. 225:735-38. 1974 With A. Ar, C. V. Paganelli, R. B. Reeves, and D. G. Greene. The avian egg: water vapor conductance, shell thickness and func- tional pore area. Condor 76: 153-58. With O. D. Wangensteen, R. R. Burton, and A. H. Smith. Respira- tory gas exchange of high altitude adapted chick embryos. Respir. Physiol.21:61-70. 1975 With R. B. Reeves and B. T. Howell. Hydrogen ion regulation, tem- perature and evolution. Am. Rev. Respir. Dis. 112:165-72. 1976 With B. dew. Erasmus. Effects of ambient pressures, He and SF6 on O2 and CO2 transport in the avian egg. Respir. Physiol. 27:53-64. 1977 With C. Carey, K. Balmas, B. Bhatia, and C. V. Paganelli. Reduction of pore area of the avian eggshell as an adaptation to altitude. Proc. Nail. Acad. Sci. U.S.A. 74:3095-98. 1978 With B. T. Howell. The OH-/H+ concept of acid-base balance: his- torical development. Respir. Physiol. 33:91-97.

HERMANN RAHN 267 1979 With A. Ar and C. V. Paganelli. How bird eggs breathe. Sci. Am. 240:46-55. 1980 With C. Carey and P. Parisi. Calories, water, lipid and yolk in avian eggs. Condor 82:335-43. 1982 With G. S. Grant, T. N. Pettit, G. C. Whittow, and C. V. Paganelli. Regulation of water loss from Bonin Petrel (Pterodroma hypoleuca) eggs. Auk 99:236-42. With H. T. Hammel. Incubation water loss, shell conductance and pore dimensions in Adele Penguin eggs. Polar Biol. 1:91-97. 1983 With J. Krog and F. Mehlum. Microclimate of the nest and egg water loss of the Eidar (Somateria mollissimaj end other waterfowl in Spitsbergen. Polar Biol. 1:171-83. 1987 With F. Mehlum, C. Bech, and S. Haftorn. Interrelationships be- tween egg dimensions, pore numbers, incubation tie and adult body mass in Procellariformes with special reference to the ant- arctic petrel (Thalassoica antarctica). Polar Res. 5:53-58. 1988 With A. J. Olazowka and H. Tazawa. A blood-gas nomogram of the chick fetus: blood flow distribution between the chorioallantois and fe tus. Respir. Physiol. 71 :315-30. With D. Swart. Microclimate of ostrich nests: measurements of egg temperature and nest humidity using egg hygrometers. 7. Comp. Physiol. B 157:845-53. 1990 With S. A. Poturalski and C. V. Paganelli. The acoustocardiogram: a noninvasive method for measuring heart rate of avian embryos in ova. J. Appl. Physiol. 69: 1546-48.

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