“…Furthermore, most of the measurements made on the volunteer subjects fell within the generally accepted "limits of normal." It is certain that reliance on these limits has caused investigators to ignore significant human variability (Sargent et al, 1959;Schreider, 1953;Williams, 1957). This variability cannot be ignored, for it arises from individuality and the manner in which individuals respond to their environment (Sargent, 195 1;Williams, 1956).…”