THE MEASURE OF METABOLISM

Owing to the efforts of a number of American investigators, many facts regarding metabolism in man have been convincingly demonstrated. The rôle of muscular activity in creating an extra demand for energy as derived from food fuel has long been recognized. Even some of the minor activities in which muscles are engaged transform energy in amounts that are readily measurable by the newer methods. The energy expended by an infant in crying, the work done in rising from the reclining posture, the muscular work involved in chewing gum—these and similar activities can be measured and their cost to the body expressed in terms of converted calories. Less well known is the stimulatory effect of recently ingested food on the metabolism. As Benedict¹ and his collaborators have lately reminded us, in reviewing the present state of knowledge in this field, heat production is greatly increased after eating, and the amount