130 W. M. Wallace, W. B. Weil and A. Taylor 



susceptible to some variation by variation of dietary intake. 

 Even in relation to skeletal tissue the possibility of variable 

 composition is limited by another parameter, i.e. protein. 

 Thus, the composition of the body achieves an independence 

 from the environment, an independence that would seem 

 essential in a living system where metabolic function is carried 

 on by protein with its critical requirement for constancy of 

 water and ionic concentration. 



The concept that the whole body or the cells of the body 

 may be enriched or depleted of their various chemical con- 

 stituents by variation of the dietary intake is widely supported 

 in the nutritional literature. By examination of retentions 

 during balance observations on growing infants, it may be 

 concluded that the higher the intake of a substance, the 

 greater will be its final concentration in the body per unit of 

 weight (Rominger and Meyer, 1927; Swanson and lob, 1933; 

 Stearns, 1939). 



Correlation of weight gains of premature infants with the 

 protein and ash content of the milk fed has shown high 

 positive correlation with the increasing ash content (Kagan 

 et al., 1955). Conversely, possible support for the concept of 

 variable body composition stems from nitrogen losses after 

 trauma. Both animals and men maintained on low protein 

 intakes lose less nitrogen after trauma than do those with 

 prior optimal intakes (Munro and Cuthbertson, 1943; Cuth- 

 bertson, 1948). Holmes, Jones and Stanier (1954) found evi- 

 dence indicating that men shifted from very low protein 

 intakes to optimal intakes retained nitrogen far in excess of 

 that calculated from weight gain and external losses. The 

 use of the terms "depletion" and "deficiency" bears tacit 

 evidence for the belief in the concept of cellular impoverish- 

 ment during nutritional deprivation. The majority of the 

 evidence for the concept of variable storage of protein and 

 minerals and loss during deprivation stems from the technic- 

 ally hazardous techniques involving measurement of external 

 balances. The possibility of low correlation between apparent 

 retentions or losses and changes in body weight has not been 



