The Significance of Body Size

For some time I have felt that doctors have created unnecessary confusion in the rules intended to take account of the different body sizes of infants, children, and adults. The difficulty arises largely from failure to utilize available knowledge of physiological relationships. Doctors know that total metabolism is considerably greater per kilogram of body weight in infants than in adults. Consequently, total metabolism rather than weight is the appropriate measure of those functions dependent on rate of metabolic turnover. Body weight is the measure of the mass of water, electrolyte, and protoplasm in which metabolic changes are taking place. In other words, body size has two dimensions. Attempts to bypass either of these dimensions fails to bring into view the relevant physiological relationships and establishes no adequate frame of reference which permits logical analysis. However, using the correct dimensions, present knowledge permits the same physiological principles to be applied to