Bio-chemistry. — "On the Influence of the Composition of the 

 Food on the Calcium output''. By Prof. B. Sjollkma. (Com- 

 municated by Prof. H. Zwaardemaker). 



(Communicated at the meeting of November 25, 1922). 



In my experiments on the influence of cod-liver oil on calcium-, 

 and phosphorus metabolism I found that the economizing efïect of 

 cod-liver oil on calcium and on phosphorus, was attended with a 

 decreased production of faeces^). The question naturally arose whether, 

 conversely, an augmented production of faeces should result from 

 an increase in the faecal output of calcium and of phosphorus. 



The answer to (his question is of great importance with regard 

 to our understanding the metabolic phenomena and the physiology 

 of the formation of faeces. The question may be looked at also from 

 a practical point, especially because in experiments with milk-cattle 

 results were repeatedly obtained of late years, which render it 

 highly probable that among the dietetic factors the mineral compo- 

 nents are often in the minimum. 



In the experiments described below we observed especially the 

 influence of the increase of the quantity of indigestible foodstuffs 

 (ballast) on the calcium- and pliosphorus-metabolism. Two ballast- 

 experiments have been performed this summer, both with rabbit III, 

 which since November 1921, was always used for metabolic exper- 

 iments, and which for chief diet was given a ration of dextrin, 

 lactose, oatstraw boiled with acid and alkali, a calcium-free salt- 

 mixture, a pure protein, viz. casein (afterward partly substituted by 

 gluten of wheat) and a few grammes of butter. 



Besides this food-mixture, wheat (whole kernels) was given in the 

 ratio 3 mixture to 1 wheat. In addition almost always 15 grms of 

 cabbage was administered per day. For some weeks the boiled oat- 

 straw was replaced by sawdust boiled with acid and alkali and the 

 cabbage by mangels or carrots. 



The calcium-determinations') were made, after destructio of the urine 

 or the faeces, titrimetrically after Mc Crudden, as well as nephelo- 



^) Jubilee-Volume Zwaardemaker- Arch, nêerl. de Physiol, t. VII, 1922. 

 ') The analyses were performed by Miss J. E. van der Zande, conservatrix, and 

 by Messrs H. Hooghoudt, analyst and H. Gieteling (volontaire). 



