398 



Whereas in either period tlie amount of calfiiini administered was 

 nearly equal, the output in the initial-period was about three times 

 that of the final-period. When comparing the values of the fore- 

 period and of the experimental period of the second experiment, 

 we see that whereas the quantity of faeces was about the double, 

 the Ca-loss in the faeces was about 1^ times greater than in the 

 initial-period. 



The calcium-output via the kidney was in the first experiment 

 during the ballastperiods higher than in the initial- and final- 

 period ; in the second experiment there was a gradual decrease of 

 calcium in the urine. This is also most likely attributable to the 

 highly negative balance. 



The figures warrant the assumption of a rise of the calcium- 

 output in the urine resulting from a great amount of ballast, if the 

 diet is not too poor in calcium. The quantity of calcium in the 

 faeces was as a rule at least double the quantity of that in the urine. 



Regarding the influence of ballast on the phosphorus output we 

 only wish to observe that it was not quite parallel to the influence 

 on the calcium-output. In the ballast-periods the phosphorus-content 

 of the faeces decreased considerably in both experiments. 



In a subsequent paper I intend to discuss the nitrogen-, and the 

 iron-outputs in these experiments, and to give the results of the 

 experiments in which we examined the influence of the alkali metals 

 in the food on the calcium- and the phosphorus metabolism. 



From the experiments here described it appears: 



1. that an increase of the amount of indigestible matter in the 

 food causes a greater loss of calcium via the intestinal canal. 



2. that not all the calcium present in the faeces is necessarily 

 derived directly from the food: a large portion of it may be given 

 off by the organism, from which we may conclude that calcium 

 plays a role in the production of faeces. 



3. that in view of this it is only under certain conditions that 

 an examination of the faeces can show whether in the food or in 

 a part of it (e.g. calcium-salts) calcium occurs in an available form. 



4. that in animals, yielding much milk, feeding with much ballast 

 enhances the danger of a negative calcium balance. 



{From the Chemical Laboratory of the Utrecht 

 Veterinary University). 



