FOLLOWING major head and neck surgery under hypothermic conditions in a prior study group1 and in the observations that constitute the experimental phase of this report, a seemingly intangible benefit appeared to accrue to the study group of patients. This could not be measured in terms of wound healing, rate of clinical recovery, or length of hospital stay because of the large source of experimental error in such clinical judgments. Defining the term "error" in the statistical sense makes the point even more obvious; error is the degree to which whatever we measure is influenced by other causes than those which are being investigated2 and is a reflection of a good many influences that lie outside the scope of the inquiry at the time of the study. The patients' past health, nature of potential home care, dependency as a basic character and personality trait, and a multitude of