142 Nathan B. Talbot and Robert Richie 



utilize but a small segment of their homeostatic capacities. 



In early infancy, the margins of safety are relatively quite 



narrow, a fact long recognized by those interested in paediatrics. 



The clinical significance of these homeostatic parameters 



300 

 SODIUM 

 mEq/m*/24* zoo 



POTASSIUM 

 inEq/m^/24» ioo 



llllllllli /f/t/vee OF PHYSIOLOGIC TOLERANCE 

 RANGE OF NORMAL DIETARY INTAKE 



/ 6 3 6 9 12 18 Z 

 BIRTH WKS. ^-MONTHS— ' 



6 e 10 12 16 20 

 YEARS ' 



Fig. 2. Estimates of the safe working ranges of intake 



for individuals of various ages and of the portions of 



these ranges used by persons taking ordinary diets 



for age. 



may be visuaUzed by considering the length of time needed 

 for individuals of various ages to lose a significant portion of 

 their body stores when totally deprived of water or certain 

 other substances (Fig. 3). In calculating these time values, 

 attention has been given to the changes in body composition 



