SUMMARY OF CHAPTER IV 



ON THE INORGANIC CONSTITUENTS OF MILK 



THE inorganic constituents of milk have formed the subject of 

 considerable investigation. As a whole, it appears that the amount 

 of the various salts which are present in cows' milk is greater than 

 the amount of the corresponding substance in human milk. The 

 chief exception has been shown to be iron. Recent investigations 

 conducted upon the amount of this mineral present in the milk 

 of women and of cows, leave little room for doubt that the iron 

 content of human milk is from two to three times as great as that 

 of cows' milk. 



The calcium content of milk has attracted much attention 

 because it was supposed that a deficiency of calcium in the 

 milk might be the cause of rickets. Although this possibility 

 cannot be absolutely set aside, the numerous investigations 

 which have been carried out show that there is no definite 

 relationship between the occurrence of rickets and the amount 

 of calcium which is found in the mother's milk in the case of 

 breast-fed children. 



Numerous experiments have been carried out with a view to 

 determining whether it was possible to increase the content of any 

 particular salt in milk by the addition of this material to the food- 

 stuff. The results obtained cannot be regarded as showing this 

 possibility to any appreciable extent, although one or two observers 

 claim to have produced a small increase in the amount present. 

 The withdrawal, however, of any particular inorganic constituent 

 found in the milk from the dietary produces an undoubted effect. 

 The content of this substance in the milk is not reduced, at any rate 

 appreciably, the organism depleting itself to maintain the normal 

 percentage of this substance in the mammary secretion. As soon, 

 however, as such depletion would injure the organism the supply of 

 milk is reduced and the output of the constituents correspondingly 

 decreased, thus preventing depletion of the maternal organism. 

 On restoring to the dietary the required amount of the inorganic 

 constituent, the amount of milk produced returns to its former 

 level. 



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