28 METABOLISM OF ORGANIC AND I X< MM !A X 1C PHOSPHORUS. 



pletely or partly, of one particular metal, say calcium. If the proper 

 ratios are not maintained in the blood, then: 



(a) Is the excretion of calcium checked wholly or partially? Dur- 

 ing the progress of his research an article appeared by Goitein 

 which disposes of this question by showing that if a rabbit received 

 less than 0.16 grams of calcium per kilo per day in its food, there was 

 a stead}' loss of calcium from the bocly. Lehmann 6 and others 

 have shown that in starvation the calcium excreted exceeds the 

 amount of this substance present in the drinking water taken. 



(b) Are the other salts of the body reduced pari passu by increased 

 excretion? This would entail a considerable fall in the total molecular 

 concentration of the blood, and as the living cells of the body and also 

 the red corpuscles are extremely sensitive to osmotic changes this 

 question may also be answered in the negative. 



(c) Is the deficiency in the food made good by certain tissues of 

 the body giving up a portion of their calcium to the blood and so 

 keeping the proper inorganic balance in this fluid ? That this would 

 be the most probable contingency may be inferred from a number 

 of facts. Forster/ who was the first to make observations on the 

 effect of insufficient calcium in the food, found that the muscles lost 

 56 per cent of their calcium content, while the bones also showed a 

 considerable diminution. Voit d found that on a calcium-poor diet 

 the bones were more brittle, the skeleton showed a smaller per- 

 centage of dry weight than in the normal animal, and that the 

 quantity of calcium in all organs of the body was more or less di- 

 minished. 



In the experiments in which rabbits were fed on oatmeal and 

 maize meal, a diet which admittedly leads to calcium starvation, 

 the ratio of the calcium of the blood to the total ash of the blood 

 remained the same as that found in the normal animal. That is to 

 say, the blood underwent no loss of calcium relative to the other 

 salts in the time allotted to the experiment a result which one might 

 anticipate from the immense importance of the salt ratios of the 

 blood. The ratio of calcium to the total mineral matter in the bones 

 was, however, inconstant, and showed fairly wide fluctuations even 

 in the normal animal. The bones can, without doubt, act as store- 

 houses of calcium and possibly of magnesium. That the}' lose 

 calcium when the animal is placed on a calcium-poor diet has been 

 proved conclusively. Voit's results, however, tend to show that the 

 bones can lose calcium relatively to the other salts, that is, by a 

 selective autolysis. The experiments on his own body metabolism 

 show that calcium can be readily stored during nitrogen retention. 



Arch, gesam. Physiol., 1906, 115 : 118. < Maly's Jahres-Ber., 1873, 3 : 251. 

 & Abs., Maly's Jahres-Ber., 1894, 23 :497. <*Zte. Biol., 1880, 16 : 55. 



