The importance of water in the preservation of health and in the treatment of disease in infancy and in childhood has been recognized for many years. The infantile organism is especially hydrolabile, probably because of its high content of body water; this content comprises over 70 per cent in the newly born infant, as against less than 60 per cent in the adult. This hydrolabile tendency is exemplified by the wide fluctuations in daily body weight of healthy infants while on constant diets, by the ready development of dehydration fever in newly born and in older infants temporarily deprived of water and by the occurrence of anhydremia as a frequent accompaniment of infantile diarrhea.
Despite the importance of water to infants, knowledge of their fluid requirements has in large measure been deduced from measurements of the average amounts of milk voluntarily withdrawn from the breast by nursing infants. These observations