397 



ment is about 100:250; in the second experiment tiie ratio is about 

 100: 150. 



That in the one experiment the rise of the calcium-output differed 

 from that in the other, is no doubt due to the very different amounts 

 of calcium administered along with the ingested food. 



The extra-ballast in the experimental period as compared with 

 the initial-period (127b of the fodder-niixlure) amounted in the first 

 experiment to about 19 mgrms per day; in the second (when no 

 sawdust plus straw, but only straw was given as ballast) to only 

 9.4 mgrms. The increase of the faecal calcium-output is therefore, 

 much larger than the amount of calcium [)reseMt in the extra-ballast. 

 That the calcium in the faeces was only for a small pai't deiived 

 directly from the food is also clear from the fact that especially 

 in the second experiment the faeces contained almost twice the 

 amount of calcium present in the ingested food. 



The increase of the amounts of faeces (air-dried) that were pro- 

 duced in the ballast periods, was very large. 



The subjoined table gives the production in grammes. 



Initial-periods 



Experimental- 

 periods 



Final-periods 



1st exp. 

 2nd exp. 



5.62 

 3.62 



11.9 and 10.5 

 7.72 



3.35 

 3.85 



The 12'/, extra-ballast in the experimental periods averaged per 

 day in the first experiment about 6,6 grms, in the second 4.7 grms. 

 These values do not differ much from those showing the increments 

 of the faeces production. 



In the first experiment the calcium-contents of the faeces (air- 

 dried) were considerably higher during the ballast-periods than in 

 the initial-period; they were lowest in the final-period. (This is most 

 likely due to the smaller quantity of calcium-salts that were admini- 

 stered). In the second experiment the calcium-content of the faeces 

 diminished after the initial-period, which is not surprising if we 

 consider the very great losses and the consequent highly negative 

 balance. In the second experiment the difference between tlie output 

 and the calcium in the food was about double the difference of the first. 



The negative balance is no doubt also answerable for the fact 

 that in the final-period of the second experiment the metabolism of 

 calcium was much more economical than in the initial-period. 



