Physiological adaptation–the ability to change so as to live more or less normally in a previously unfavorable or stressing environment–is one of the most universal properties of living things. However, the native ability of animals to adjust to variations in their environment has to a large extent been sacrificed in breeding animals for modern high standards of production.

The above progress report is based on Research Project No. 1817. This work is also supported by a research grant, No. H-1920, from the National Heart Institute, U. S. Public Health Service.

The White Mountain High-Altitude Research Station in Mono County has laboratories at elevations of 10,000', 12,500', and 14,250'. Nello Pace, Professor of Physiology, University of California, Berkeley, is Operations Director.