MINERAL METABOLISM 



319 



TABLE V 



infants, Cronheim and Mill lor on the retention found in metabolism ex- 

 periments extending over 35 days, and Meyer on the metabolism of fast- 

 ing. Tobler and Noll report a metabolism experiment on a 2^> months 

 old baby giving the average retention per day on an average daily gain of 

 24.3 g., and for the sake of comparison their values for retention have been 

 multiplied by 4, to make approximately a 100' g. gain in weight, and arc 

 included in Table V. Bartlett's estimate that 1.7 g. ash must accompany 

 every gram of 2v laid down is probably within these limits. He considers 

 0.05-0.8 g. Ca per day a normal deposit: Hertcr considers 0.1 g. CaO the 

 daily deposit necessary for normal growth. Apparently gain in weight 

 is due to such variable proportions of bone, protein, water and fat that 

 only an approximate estimate of the mineral need can be made on this 

 basis. Children 6-7 years old should get 0.3-0,5 g. CaO per clay, 14 years 

 old, 0.6-0.0 g., in order to support normal growth of bones (Ilerbst). 



It is generally conceded that human milk contains the mineral con- 

 stituents in the ideal proportions for growth, although Dibbelt and Aron(fr) 

 point out that the breast-fed baby's need of lime may exceed its supply in 

 the first six months of life, and thereafter the supply exceeds the need. In 

 this connection it is worth while to refer to recent very painstaking analyses 

 of woman's milk by Schloss(a) and Holt (b) and of cows' milk by Trunz 

 who show a colostrum period consisting of the first 12 days and character- 

 ized by high ash content, a transition period to the end of the 4th week after 

 which the composition remains about; constant until the 10th month. This 

 can best be summarized, arid the difference -between human and cow's milk 

 displayed in tho following table (VI). Schloss compared the complete 

 24-hour samples of milk from 8 w r et nurses and found a marked paral- 

 lelism between the X and total ash. The lower content of Ca in human 

 milk is compensated by a much better absorption. 



The feeding of vegetables to young babies (6-7 months old) has recently 

 been shown to exert a favorable influence on their growth. The increased 

 quantity of salts, their especially favorable chemical nature, or the vitamin 

 content are variously suggested to explain this effect. Since boiling vege- 

 tables in water causes a considerably greater loss of salts than steaming, the 

 latter method of cooking is recommended (Courtney; Fales and Bartlett). 



