Beginning in the mid-1930s the comparative physiologists Laurence Irving and Per Fredrik Scholander pioneered the study of diving mammals, particularly harbor seals. Although resting on earlier work dating back to the late nineteenth century, their research was distinctive in several ways. In contrast to medically oriented physiology, the approaches of Irving and Scholander were strongly influenced by natural history, zoology, ecology, and evolutionary biology. Diving mammals, they argued, shared the cardiopulmonary physiology of terrestrial mammals, but evolution had modified these basic (...) adaptive processes in extreme ways. In particular, seals’ remarkable ability to hold breath, lower metabolism, produce energy anaerobically, and resist asphyxiation, provided a sharp contrast with terrestrial mammals, including humans. This diving physiology was an extreme elaboration of a general regulatory mechanism that allowed seals and other diving mammals to remain active underwater for extended periods. The decrease in heart rate referred to as bradycardia or the “diving reflex” was highly developed in diving mammals, but also found in less developed form in many other organisms faced by asphyxia. It therefore served as a kind of “master switch” for lowering metabolism in diving, hibernation, parturition, drowning, and other physiological responses involving lack of oxygen. Studying bradycardia unified a wide diversity of physiological phenomena, while also providing a context for contrasting the physiological responses of various species, including humans. Conducted in the laboratory and the field, this research served as a bridge between a comparative physiological ecology focused on non-human species and a human-centered general physiology. (shrink)

In the first half of the twentieth century the attention of American and European researchers was drawn to the area of ‘extreme physiology’, partly because of expeditions to the north and south poles, and to high altitude, but also by global conflicts which were fought for the first time with aircraft, and involved conflict in non-temperate zones, deserts, and at the freezing Eastern front. In an attempt to help white Euro-Americans survive in extreme environments, physiologists, anthropologists, and explorers studied indigenous (...) people’s bodies, cultures, and technologies. This paper will sketch an outline of the science of white survival in three ‘extreme’ environments: the Antarctic and Arctic; high-altitude; and the Australian desert, with a particular focus on the ways in which indigenous populations were studied, or in some cases ignored, by Western biomedical scientists—despite their crucial and systematic contributions to the success of experiments and expeditions. Particularly focusing on altitude, and on blood in both its symbolic and literal sense, the article shows how assumptions about race, indigeneity, civilisation, and evolution shaped the ways White Westerners understood their own bodies as well as those of the people they encountered in cold, high and hot places on the earth. Despite new discoveries in physiology and evolutionary science, old racialised assumptions were maintained, especially those that figured the temperate body as civilised and the tropical body as primitive; and in at least one case it will be shown that these racialised assumptions significantly altered, if not retarded, the science of respiratory physiology. (shrink)