Aeromedical Laboratory Research Articles

The Lighter Side of Aviation Medicine during World War 2: Aero Medical Training Cartoons

The air war of 1939‐1945 was the world’s first high‐speed, high‐altitude air war. The limiting factor in aerial combat was no longer the warplane’s performance, but rather, the aviator’s limited tolerances for exposure to the rarefied, anoxic, subzero atmosphere. Aviators flew unpressurized planes to altitudes of 20,000‐35,000 feet during reconnaissance and bombing missions to evade enemy interceptors and anti‐aircraft fire. At altitude, warfighter performance could be impaired by anoxia, decompression sickness, hypothermia & frostbite. Escaping from a disabled aircraft at high‐altitude also presented physiological challenges, including anoxia, frostbite, and parachute opening shock G‐forces. High‐performance fighter aircraft also subjected pilots to G‐forces during violent dogfighting maneuvers that left them temporarily blinded and unconscious from reduced brain blood flow. One of the challenges for the “medical men” was teaching young airmen, from all walks of life, the fundamentals of aviation physiology and how to use their oxygen equipment in this new physiological air war. This task fell in large part to the physiologists of the U. S. Army Air Forces (USAAF) and U. S. Navy (USN). The USAAF used training cartoons known as Thought Pictures to illustrate conceptually difficult topics in anatomy, physiology, and the physics of the atmosphere (Figs. 1 & 2). Thought Pictures, drawn by the artist/author Eric Sloane (1905‐1985), were combined with concisely written text in the popular training manual, Your Body in Flight (1943, 1944), which was published by the Aero Medical Laboratory at Wright Field, Dayton, Ohio. The USAAF also published aero medical training cartoons in Air Force Magazine.In the USN, a popular training cartoon character was the accident prone, bumbling airman, Dilbert Groundloop,drawn by satirist Robert C. Osborn (1904–1994). The USN Bureau of Medicine also highlighted important aero medical issues using comical illustrations in the widely distributed Senseseries; e.g. Oxygen Sense, High Altitude Sense, “G” Sense& Parachute Sense. Likewise, the School of Aviation Medicine, U. S. Naval Air Station, Pensacola, FL, published altitude training cartoons in CONTACTmagazine. Even Boeing and Lockheed aircraft manufacturing companies published humorous cartoons in Boeing News Magazine and Hangar Flying to reinforce the medical dangers of altitude flying to their test pilots and flight engineers. Finally, those mischievous pixies of the air, the Aero Medical Gremlins, proved to be another valuable training tool (see author's Aviation Gremlins abstract). Together, these humorous illustrations enabled America’s aviation physiologists and flight surgeons to drive home the serious nature of the physiological challenges of combat flying to aviators, while at the same time, presenting difficult material in an easily remembered format that was also amusing and entertaining for airmen soon to be facing life or death on every mission. Aero medical cartoons worked so well as a training tool that interrogation of German aviation physiologists at the end of the war revealed a professional admiration by them for the depth of understanding that American aviators had regarding the physiological effects of high‐altitude and the physiologic principles underlying their protective flight gear.

Ethics in retrospect: Biomedical research, colonial violence, and Iñupiat sovereignty in the Alaskan Arctic.

Kaare Rodahl, a scientist with the US Air Force's Arctic Aeromedical Laboratory, spent much of the 1950s traveling to villages in the Alaskan Arctic to conduct research on cold acclimatization. Four decades later, it was discovered that during one such study, he had administered radioactive isotopes of iodine-131 to over one hundred Alaska Native research subjects without their knowledge or consent. This news broke just as Alaska Native communities were attempting to recover from a series of revelations surrounding other instances of Cold War radiation exposure. In response, two major federal investigations attempted to determine whether Rodahl had adhered to ethical regulations and whether his actions could be expected to have a lasting health impact on former research subjects. The National Research Council, framing the study as a singular event in the Cold War past, found that research subjects had been 'wronged, but not harmed'. The North Slope Borough, a powerful Alaska Native municipal government, countered this finding with their own investigation, which identified both the study and the subsequent federal inquiries as facets of the still-unfolding process of American settler colonialism in Alaska. In doing so, the North Slope Borough contested the authority of federal agencies to set the terms by which ethics could be retrospectively judged. This article argues that exploring how competing ethical regimes represent the relationship between violence and time can help us better understand how institutionalized bioethics reproduces settler colonial power relations.

The Lab and the Land: Overcoming the Arctic in Cold War Alaska

The militarization of Alaska during and after World War II created an extraordinary set of new facilities. But it also reshaped the imaginative role of Alaska as a hostile environment, where an antagonistic form of nature could be defeated with the appropriate combination of technology and training. One of the crucial sites for this reformulation was the Arctic Aeromedical Laboratory, based at Ladd Air Force Base in Fairbanks. In the first two decades of the Cold War, its employees conducted numerous experiments on acclimatization and survival. The laboratory is now best known for an infamous set of tests involving the application of radioactive tracers to indigenous Alaskans--experiments publicized by post-Cold War panels established to evaluate the tragic history of atomic-era human subject research. But little else has been written about the laboratory's relationship with the populations and landscapes that it targeted for study. This essay presents the laboratory as critical to Alaska's history and the history of the Cold War sciences. A consideration of the laboratory's various projects also reveals a consistent fascination with race. Alaskan Natives were enrolled in experiments because their bodies were understood to hold clues to the mysteries of northern nature. A scientific solution would aid American military campaigns not only in Alaska, but in cold climates everywhere.

David Bruce Dill: A Man of Many Seasons and Environments—Committed to Life, Heat, and Altitude

Section editor’s note: This paper on the professional life of Dr David Bruce Dill is a departure from the typical ‘‘Lessons From History’’ commentary on a classic original scientific article relevant to wilderness medicine. It is hoped that readers will find this short vignette of Dr Dill, a personality who contributed so much to the field of environmental physiology, enjoyable and informative reading. David ‘‘Bruce’’ Dill (1891‐1986) was widely and affectionately known throughout his life as a scientist, colleague, and friend. As a pioneer in the fields of exercise and environmental physiology, physiochemical properties of blood, and aging, he made significant and lasting contributions. The 20 years Dill spent as research director of Harvard’s renowned Fatigue Laboratory was an era of highly productive research in high-altitude, tropical, and desert environments. His pursuit of research and passion for life lead him to many environments, starting in his early years at Harvard and continuing until his 95th year. Born in Kansas, Dill was raised by relatives after the death of his parents and ultimately moved to California. He was graduated from Occidental College in Los Angeles with a bachelors of science degree in chemistry and received a masters of arts degree and a PhD in chemistry from Stanford University. Through his association with his doctoral advisor, Professor C. L. Alsberg, he obtained a National Research Council Fellowship (1925‐1927) at Harvard University with Lawrence J. Henderson. 1 While at Harvard, Dill was introduced to many scientists, establishing many lasting friendships. He worked with A. V. Bock during research on physiochemical properties of blood at the Massachusetts General Hospital, and their professional and personal relationship continued in the following years. In 1927, through the encouragement of A. V. Hill, both Dill and Bock wrote an update of Bainbridge’s monograph, The Physiology of Muscular Exercise . 2 This publication is considered pioneer work that made a lasting contribution to the field of exercise physiology. It was Dill’s association with L. J. Henderson that led

The uncertainty of the pendulum method for the determination of the moment of inertia

The purpose of this study was to quantify the uncertainty of the pendulum method for determining the moment of inertia of an object using various suspension distances. Experimental data were collected on a known geometric solid and partial differential equations were derived to calculate the uncertainty. Repeated measures were used to estimate the errors of the mass, period of oscillation, and distance measurements from the axis to the centre of mass. The results showed that the pendulum method was relatively insensitive to measurement errors of mass but was quite sensitive to errors in the period of oscillation. It was also found that the uncertainty of the pendulum method could be drastically reduced to less than 3% by suspending the object with the axis located at the radius of gyration. Most studies using the pendulum method to determine limb inertial properties have adopted a proximal suspension, including the often cited work by Dempster [Dempster WT. Space requirements for the seated operator. W ADC Technical Report 55–159. Ohio: Aero Medical Laboratory, Wright Air Development Centre, Air Research and Development Council, Wright-Patterson Air Force Base; 1955]. The results suggest that validation of imaging techniques to determine inertial properties should use geometric solids in addition to the pendulum method where the object is suspended at a distance estimated to be the radius of gyration. It is further recommended that the uncertainty be reported whenever it is necessary to use the pendulum method.

Retinal haemorrhage during sustained hypobaric hypoxia in rats.

Acta Physiologica ScandinavicaVolume 155, Issue 4 p. 463-464 Retinal haemorrhage during sustained hypobaric hypoxia in rats H. OSADA, Corresponding Author H. OSADA Department of Environmental Physiology, Aeromedical Laboratory, JapanDepartment of Environmental Physiology, Aeromedical Laboratory, JASDF, 1–2-10 Sakae-cho, Tachikawa, Tokyo, 190, Japan.Search for more papers by this authorY. KANAMARU, Y. KANAMARU Department of Environmental Physiology, Aeromedical Laboratory, JapanSearch for more papers by this authorS. MARUYAMA, S. MARUYAMA Department of Environmental Physiology, Aeromedical Laboratory, JapanSearch for more papers by this author H. OSADA, Corresponding Author H. OSADA Department of Environmental Physiology, Aeromedical Laboratory, JapanDepartment of Environmental Physiology, Aeromedical Laboratory, JASDF, 1–2-10 Sakae-cho, Tachikawa, Tokyo, 190, Japan.Search for more papers by this authorY. KANAMARU, Y. KANAMARU Department of Environmental Physiology, Aeromedical Laboratory, JapanSearch for more papers by this authorS. MARUYAMA, S. MARUYAMA Department of Environmental Physiology, Aeromedical Laboratory, JapanSearch for more papers by this author First published: December 1995 https://doi.org/10.1111/j.1748-1716.1995.tb09996.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume155, Issue4December 1995Pages 463-464 RelatedInformation

Frederick A. Milan (1924-1995)

Frederick A. Milan died on 28 January 1995 after a series of strokes and related illness of several years. ... His activities around the polar regions of the world are well known and fondly remembered. Fred was Professor Emeritus of Human Ecology and Anthropology at the University of Alaska, Fairbanks. ... His work as an assistant on the Harvard Peabody Museum Anthropological Expedition to the Aleutian Islands in 1949 heightened his interest in the Arctic. It also impressed upon him the utility of studying Russian for understanding the history of the region. Fred worked in the summers of 1950 and 1952 as an archaeological assistant at Deering and Kodiak, Alaska. He was a weather observer on the Juneau Icefield Research Project in the summer of 1951. His major scholastic interests were in anthropology and linguistics, and he graduated in 1952. In 1953 Fred began several years of association with the former United States Air Force Arctic Aeromedical Laboratory near Fairbanks. ... [In 1954] he and other Arctic Aeromedical Laboratory personnel participated in the Mount Wrangell Research Project, a high-latitude cosmic ray study. His role was as a collaborator in a study of high altitude acclimatization of the team members. ... Fred undertook graduate study at several institutions: the Universities of Oregon, Wisconsin and Copenhagen, and the London School of Economics. His linguistic skills became well developed, and he was especially interested in the Inuit language and culture. He spent one winter in northern Sweden traveling and living with a nomadic Sami family. Back in Alaska in 1956, he began his close association with the Inupiat Eskimo village of Wainwright, Alaska. His ability to speak the language enabled him to gain the villagers' confidence and elicit genealogical information, and endeared him to the people. These activities led eventually to successful completion of his M.S. and Ph.D. degrees at the University of Wisconsin. ... In the 1960s Fred played an important role in establishing a worldwide study of northern people as part of the Human Adaptability section of the International Biological Program. ... He was a longtime advocate for multidisciplinary study of the needs for health care delivery and for the international exchange of information about circumpolar health problems and research efforts. In 1967 Fred, Dr. C. Earl Albrecht and colleagues in Alaska and other parts of the United States, Canada, Sweden, Norway, Denmark, Iceland, Greenland and the Union of Soviet Socialist Republics organized, with the support of the Arctic Institute of North America, the First International Symposium on Circumpolar Health. The symposium was held at Fairbanks in July 1967, and these meetings have continued at three-year intervals at various circumpolar locations. Fred was the president of the Sixth International Congress on Circumpolar Health held at Anchorage in 1984. ... During the 1970s and 1980s Fred was a faculty member at the University of Alaska, Fairbanks. He was a much-respected teacher, and he was noted for conveying his enthusiasm for scholarly work and his respect for the people of anthropological study to students and colleagues. The Fred Milan we knew was a genuine free spirit--he looked at the world through eyes wide with perceptive curiosity and interpreted it with kindness and good humor. We have been made richer and wiser by sharing in some of his generous and stimulating life.

Thomas Saunders English, 1928-1985

After three years of illness, Tom English passed away in Seattle, Washington, on 5 January 1985. ... Tom was born and grew up in Washington, D.C. The undergraduate years, 1946 to 1950, were spent at Iowa State University in Ames, first as a journalism major, later as a zoology student. He continued at Ames with graduate work in zoology and statistics, receiving a master's degree in 1951 with a thesis on age, growth, and life history of carps in a local lake. ... Before receiving his doctorate at the University of Washington in 1961, Tom did graduate studies at the University of Oslo and in Bergen, Norway (1954-55); he also served in the U.S. Air Force at Fairbanks and near the North Pole (1956-58) and spent one year as instructor in fisheries biology at the University of Alaska (1958-59). His Ph.D. thesis treated the distribution and abundance of planktonic flatfish eggs in Puget Sound. Tom joined the teaching faculty of the then Department of Oceanography of the University of Washington in 1959. The next quarter of a century of his professional life was more than filled with teaching, research, participation in base-line studies for the state and federal governments and administrative work in the department. ... Tom's research interests revolved around problems of sampling design and the plankton of the Arctic Ocean. ... The common method of estimating stock size of fishes with pelagic eggs from integrating areas within contour lines of egg abundance was critically assessed and a better method was proposed. ... Tom chose to discharge his ROTC obligations of undergraduate days by entering the Air Force ... and, apparently, elected to be detailed to the Arctic Aeromedical Laboratory outside Fairbanks. ... he spent two summers and autumns on Drift Station Alpha, an ice floe near the North Pole .... The biological investigations were performed under contract with the Arctic Institute of North America. Besides being among the first to SCUBA-dive under the ice ..., Tom established in great detail what earlier polar investigators could only suggest: that the annual phytoplankton cycle under the ice is primarily driven by underwater light, which in turn depends more on snow melt than incident radiation. ... In the mid-sixties, Tom's continuing interest in the plankton of the Arctic Ocean was directed to Fletcher's Ice Island (also called T-3). Plankton collections were made in eight summer seasons between 1966 and 1973, and in all or most other months from 1968 through April 1974. The island drifted during this time from about 75° N north of Point Barrow, to beyond 85° N, to north of Ellesmere Island. In addition, summer collections were made in 1975 at the main camp of the Arctic Ice Dynamics Joint Experiment in the Beaufort Sea. Predominantly north of 80° N, Tom, his students, and his assistants collected the following (approximate numbers): 5500 samples each for temperature and salinity, 5000 for oxygen, 3300 each for phosphate, nitrate, and silicate, 6000 for chlorophyll, and 4000 measurements of photosynthesis (14C); further, 5800 phytoplankton and 11 000 zooplankton samples were gathered .... While the emphasis was on the upper layers, some sampling extended to the bottom. The enormous, truly unique body of analyses has only partly been evaluated .... Tom chose not to spend much of his energy on the dissemination of research results through publications but, like a real college teacher, to devote his time primarily to transmitting knowledge by classroom teaching, as well as guiding students doing research. ...

46. Further evidence of temperature independence of the mammalian biological clock: G. Edgar Folk, Jr., and Roger S. Hedge (Arctic Aeromedical Laboratory and Artic Research Laboratory, Fort Wainwright and Barrow, Alaska)

46. Further evidence of temperature independence of the mammalian biological clock: G. Edgar Folk, Jr., and Roger S. Hedge (Arctic Aeromedical Laboratory and Artic Research Laboratory, Fort Wainwright and Barrow, Alaska)

Arctic Aeromedical Laboratory, United States Air Force

Journal Article Arctic Aeromedical Laboratory, United States Air Force Get access H. F. Drury H. F. Drury Search for other works by this author on: Oxford Academic Google Scholar BioScience, Volume 14, Issue 5, May 1964, Pages 49–51, https://doi.org/10.2307/1293202 Published: 01 May 1964

Gravitational Stress in Aerospace Medicine

Heretofore, information on the physiological effects of gravitational stress has been difficult to embrace because it has been scattered among government technical reports and in a wide variety of journals. With the advent of rocketpropelled vehicles of unlimited speed and the recent entrance of man into space, there came an urgent need to compile and review the literature. This task was given to 2 members of Wright Field Aero Medical Laboratory, which organization sponsored this volume, one of a series on aviation medicine and space biology from the Guggenheim Center for Aviation, Health, and Safety at the Harvard School of Public Health. The editors, Drs. Otto H. Gauer and George D. Zuidema, enlisted some 12 other enthusiastic contributors from the same and several other laboratories. In the foreword, Col. John Paul Stapp, a pioneer in this field of research, considers it most appropriate for this monograph to come from 2

Histochemistry of the connective tissue of the cochlea.

The LaryngoscopeVolume 71, Issue 1 p. 1-19 Article Histochemistry of the connective tissue of the cochlea†‡§ Pedro L. Mangabeira-Albernaz M.D., Pedro L. Mangabeira-Albernaz M.D. St. Louis, Mo. Assistant Otolaryngologist, Escola Paulista de Medicina, Sao Paulo, Brazil Research Assistant in the Department of Otolaryngology, Washington University School of MedicineSearch for more papers by this author Pedro L. Mangabeira-Albernaz M.D., Pedro L. Mangabeira-Albernaz M.D. St. Louis, Mo. Assistant Otolaryngologist, Escola Paulista de Medicina, Sao Paulo, Brazil Research Assistant in the Department of Otolaryngology, Washington University School of MedicineSearch for more papers by this author First published: January 1961 https://doi.org/10.1288/00005537-196101000-00001Citations: 7 † A thesis presented to the Graduate Board of Washington University in partial fulfillment of the requirements for the degree of Master of Arts. ‡ This research was supported in part by the United States Air Force under Contract No. AF33(616)-3637, monitored by Aero Medical Laboratory, Directorate of Research, Wright Air Development Center, Wright-Patterson Air Force Base, Ohio, and in part by research grant No. B1791, Public Health Service. Reproduction in whole or in part is permitted for any purpose of the United States Government. § From the Department of Otolaryngology, Washington University School of Medicine, St. Louis, Mo. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume71, Issue1January 1961Pages 1-19 RelatedInformation

Changes in the vestilbular labyrinth with intense sound.

The LaryngoscopeVolume 69, Issue 12 p. 1478-1493 Article Changes in the vestibular labyrinth with intense sound.†‡§ Pedro L. Mangabeira-Albernaz M. D., Pedro L. Mangabeira-Albernaz M. D. St. Louis, Mo.Search for more papers by this authorWalter P. Covell M. D., Walter P. Covell M. D. St. Louis, Mo.Search for more papers by this authorDonald H. Eldredge M. D., Donald H. Eldredge M. D. St. Louis, Mo.Search for more papers by this author Pedro L. Mangabeira-Albernaz M. D., Pedro L. Mangabeira-Albernaz M. D. St. Louis, Mo.Search for more papers by this authorWalter P. Covell M. D., Walter P. Covell M. D. St. Louis, Mo.Search for more papers by this authorDonald H. Eldredge M. D., Donald H. Eldredge M. D. St. Louis, Mo.Search for more papers by this author First published: December 1959 https://doi.org/10.1288/00005537-195912000-00002Citations: 18 † This research was supported in part by the United States Air Force under Contract No. AF33(616)-3637, monitored by Aero Medical Laboratory, Directorate of Research, Wright Air Development Center, Wright-Laboratory, Air Force Base, Ohio, and in part by research grant No. B 1791, Public Health Service. ‡ From the Department of Otolaryngology, Washington University School of Medicine, St. Louis, Mo. § Reproduction in whole or in part is permitted for any purpose of the United States Government. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume69, Issue12December 1959Pages 1478-1493 RelatedInformation

Permanent Deafness after Continuous and Spaced Exposures to Noise

The auditory sensitivity of the cat as measured by the behavioral audiogram is severely impaired after a 2-hr exposure to a broad band (about 200–4000 cps) of thermal noise at an over-all level of 115 db. An exposure at this level with a duration of only 7.5 min produces no permanent change in the cat's auditory sensitivity. In the present experiment, four groups of four cats each were exposed according to the following schedule. Group I received a 2-hr exposure to the noise which was continuous in time. The other groups received the noise in sixteen, 7.5-min doses. These doses were spaced at one hour intervals for group II, 6-hr intervals for group III, and 24 hr intervals for group IV. Since the over-all level of the noise was 115 db for all groups, anc since all cats were exposed for a total of 2-hr, all cats were exposed to the same total noise energy. Persistent threshold shifts averaged over the frequency range from 125 to 16 000 cps are approximately as follows: group 1, 38 db; group II, 16 db; group III, 8 db; and group If, 0 db. Details of the audiograms, of the changes in the threshold shifts during a series of exposures, and of the recovery after the cessation of the exposures will be discussed. [This research was supported by the U. S. Air Force under Contract No. AF 33(616)-3844, monitored by Aero Medical Laboratory, Directorate of Research, Wright Air Development Center, Wright-Patterson Air Force Base, Ohio.]

Multidimensional Scaling Approach to the Determination of Basic Psychological Parameters for Pure Tones

The multidimensional scaling model of successive intervals was applied to investigate the dimensionality of auditory perception of pure tones. The stimuli consisted of 16 pure tones. Thirty-nine observers made distance judgments of similarity between stimuli. These interstimuli distances were analyzed mathematically to reveal the minimum number of dimensions necessary to account for the distances between stimuli. The results of the analysis indicated that two factors, pitch and loudness, were fairly well defined. A third factor, not as well defined, appeared to relate to pitch. The purpose of the study was to evaluate the multidimensional scaling method for use in auditory areas where the dimensions are not well known, and, since the anticipated dimensions, pitch, and loudness, were revealed, proposed use of the model in other auditory areas is supported. [This research was supported in whole by the U. S. Air Force under Contract No. AF 33(616)-3644, monitored by the Aero Medical Laboratory, Wright Air Development Center.]

Masking of Tones by Noise for the Cat

Masked thresholds were obtained by the method of behavioral audiometry for each of four cats at each of nine frequencies (octave steps from 125 to 32 000 cps). Masking stimuli were bands of noise centered about each test frequency. Estimates of critical band width (K) were obtained from data on frequency discrimination for the cat reported by Elliott et al. (MPA, 1959). The noise bands were adjusted in width to be 3 to 10 db wider than these estimated K's. Since preliminary data at 2000 cps show the signal-to-noise ratio at threshold to be constant for the cat when masking exceeds 10 db, the intensities of the noise bands were chosen to produce 20 db or more of masking. K is defined as the signal-to-noise ratio at the masked threshold. The function relating K to frequency for the cat parallels that for man, but is 4 to 5 db larger at most frequencies. The estimates of K based on the frequency-discrimination data for the cat are in reasonable agreement with these findings. [This research was supported by the U. S. Air Force under Contract No. AF 33(616)-3844, monitored by Aero Medical Laboratory, Directorate of Research, Wright Air Development Center, Wright-Patterson Air Force Base, Ohio.]

Minimum Audible Field of the Cat

In the course of our studies of persistent and temporary threshold shifts in the cat, audiograms have been obtained on a total of 39 monaural cats. These cats were trained and the thresholds were obtained by methods similar to those used in previous investigations. There is good agreement between our results and those from various laboratories, e.g., Neff and Hind [Acoust. Soc. Am. 27, 1955]. Intra-cat and inter-cat variabilities in thresholds will be presented for three modifications of the psychophysical method of limits. Details of the methods and their practicability will be discussed. [This research was supported by the U. S. Air Force under Contract No. AF 33(616)-3844, monitored by Aero Medical Laboratory, Directorate of Research, Wright Air Development Center, Wright-Patterson Air Force Base, Ohio.]

Temporary and Persistent Threshold Shifts for the Cat

The auditory sensitivity of the cat was measured by the method of behavioral audiometry before and at intervals after exposure to a broad band (about 200–4000 cps) of thermal noise. Temporary threshold shifts (TTS's) are reported for an exposure with duration of 15 min and an over-all level of 105 db. Although the cats show more loss than expected for man, TTS audiograms have the same general features as those for man. Persistent threshold shifts (PTS's) up to 55 db are induced in the cat by exposure to the noise at an over-all level of 115 db and durations of of 14, 12, and 2 hr. Over this range, PTS can be described as an increasing function of the logarithm of the noise duration. In these experiments, PTS and TTS audiograms have different shapes. PTS's appear at lower frequencies than TTS's. Histological findings that show the extent and severity of cochlear injuries after exposure at the 115-db level are described. There were slight to moderate injuries in the organ of Corti for the 15-min exposure, moderate for the 30-min exposure, and moderate to severe for the 2-hr exposure. [This research was supported by the U. S. Air Force under Contracts Nos. AF 33(616)-3844 and AF 33 (616)-3637, monitored by Aero Medical Laboratory, Directorate of Research, Wright Air Development Center, Wright-Patterson Air Force Base, Ohio.]

Detection and Evaluation of Space Radiations

In the very near future man will escape from his terrestrial environment and venture into space. The first flights will be limited space voyages circling the earth only one or sereral times at altitudes from 100 to 500 miles. As technological advances permit, these space journeys will become longer in duration and farther from earth until travel between planets in our solar system is accomplished. Ultimately of course, travel outside our solar system is envisioned. The hazards of space flight are numerous. An environment paralleling that of the earth's must be simulated as closely as possible inside the space capsule. In providing such an environment, those problems of air regeneration, temperature control, pressure control, etc., are overcome. One potential hazard from which man in space cannot be effectively protected is radiation. Therefore, the intensity of space radiations and their biological effects must be evaluated prior to prolonged space journeys if such journeys are to be accomplished without undue risk. The aeromedical field laboratory is now studying a space radiation detection system which would be capable of detecting and identifying the several forms of space radiation and the intensity of each form. Once the types and intensities of radiation prevalent in space are ascertained, it will be possible to study, in earth laboratories, the biological effects of most of these radiations.

Space medical research.

SPACE medicine, today, can look back upon a ten-year history. It came officially into being in February, 1949, with the foundation of a special department of space medicine at the School of Aviation Medicine, Randolph Air Force Base, Texas, by its commandant, Major General Harry G. Armstrong. At about the same time preparations for animal experiments in rockets were started at the Aero Medical Laboratory, Wright–Patterson Air Force Base, Dayton, Ohio. Facilities available for these grand-scale experiments, at Holloman Air Force Base, New Mexico, later became an independent institution under the name of Aero Medical Field Laboratory.At that time . . .