THE INORGANIC CONSTITUENTS OF MILK 

 The average figures obtained were as follows : 



57 



The calcium content of human milk evidently varies within 

 very wide limits, although usually at about 0-04 mg. per 100 c.c. of 

 milk. The content of the milk of each individual is approximately 

 constant, although there is a tendency to fall in the later months 

 of lactation. 



Dibbelt (2), taking figures obtained by Thomas for the total ash 

 of infants, concluded that the child frequently had to grow on a deficit 

 of calcium in the early months. He regards this as a physiological 

 arrangement to secure the transference of lime salts from the 

 interior parts of long bone to the outer parts, a transference which 

 has long been known to occur and which appears to be necessary 

 for growth. He believes that '04 to -05 per cent, of calcium is 

 sufficient for the infant, so that the needs of the child would there- 

 fore appear to be met in the majority of cases. The amount taken 

 in will also clearly be dependent upon the amount of milk taken, 

 which has been shown to vary very considerably with different 

 children. 1 



Several authors have endeavoured to trace a connection between 

 the output of calcium and other constituents of the milk, chiefly 

 in relation to fat. 



Hoobler studied the metabolism of a child of nine months on 

 low, medium, and high fat diets, i.e. 2'i per cent., 4 per cent., and 

 5-4 per cent, of fat respectively. In low fat feeding calcium was 

 withdrawn from the body, more calcium being found in the faeces 

 than was present in the food. In high fat feeding 54*57 per cent, 

 of the calcium was retained. The greatest nitrogen and phosphorus 

 intake occurred with a medium fat diet. 



Some relationship appears to exist between the calcium, nitrogen, 

 and phosphorus. Schloss and Frank, studying the metabolism of 

 children in the early stages of rickets, found that there was a high 

 but rather unsteady nitrogen retention, but a bad retention of 

 calcium and phosphorus. The addition of fat to the food, in the 

 form of cod liver oil, led to an increased nitrogen output, but steadied 

 the nitrogen balance. The addition of calcium phosphate raised 

 the calcium balance and increased the retention of phosphorus. 



Aschenheim finds that in infants taking a normal diet with 

 sufficient fat, calcium is excreted in the faeces only, but when the 



1 See Chap. VIII. 



