Extensive literature has been collected concerning the folkways, physical anthropology, and language of the Lapps. This literature dates from the Germania of the Greek historian Tacitus, and includes references to the Lapps in 13th Century Icelandic Sagas, works by Linnaeus (Karl von Linne), and the autobiographies: Muittalis samid birra, by Johan Turi, and En Nomad och Hans Liv, by Anta Pirak. From the foregoing description, it can be seen that some of the Lapps, especially the nomadic ones, are a meat-eating people, living an arduous life in the cold. In contrast to the Eskimos, who have under similar conditions, little is known about the physiology of the Lapps. This knowledge could be obtained through physiological field investigations. Both the Lapps and the Eskimos have adjusted culturally to their environment. Possibly the former have adjusted their physiology as well.