BORIC ACID AND BORAX. 225 



between the preservative and after periods, while in each case the 

 negative number is smaller than for the fore period. The explanation 

 of the fact that in this series the quantity of phosphoric acid eliminated 

 is greater than that found in the food, is not evident. It may have 

 some connection with the advent of warm weather, but this is only a 

 suggestion and not in any sense an explanation of this anomaly. 



COMPARISON OF PHOSPHORIC- ACID BALANCES. 



These data show notable variations in the quantity of phosphoric 

 acid excreted during the period of the observation. In order to bring 

 together the whole of the data for comparison, as was done in the case 

 of the nitrogen balance, there are collected in the following tabular 

 statement the mean values obtained from the phosphoric-acid balance 

 during the several series and periods of the series just mentioned. 



Gram. 



Fore periods -f 0. 119 



Preservative periods . 133 



After periods -f .127 



These collective data show that, while the influence of the preserva- 

 tive is not very marked on the metabolism of phosphorus and phos- 

 phoric acid, there is a distinct tendency to increase the quantity of 

 phosphoric acid excreted during the period of the administration of 

 the preservative. 



PERCENTAGE ELIMINATED. 



The marked differences in the daily percentages of phosphoric acid 

 eliminated are chiefly explicable, as has been already intimated, by the 

 fact that no attempt was made to separate the feces corresponding to 

 a given quantity of food for twenty-four hours by the use of powdered 

 charcoal or otherwise. The result is, therefore, that, by reason of the 

 great daily differences in the quantity of urine and feces excreted, the 

 daily percentages of phosphoric acid excreted vary much more widely 

 than would be the case if the total quantity of feces and urine from 

 the food for the period of twenty-four hours were examined as a whole. 

 The average percentage excreted for the periods in each case is deter- 

 mined by dividing the total weight of phosphoric acid eliminated by 

 the total weight contained in the food. The mathematical average of 

 the separate averages of the individual cases would be slightly differ- 

 ent from this figure. It may be added also in this connection that the 

 phosphoric acid, that is, P 2 O 5 , which is considered includes not only 

 the total phosphorus in frhe food and in the excreta in the form of 

 phosphoric acid, but also the organic phosphorus calculated to that 

 form of combination. 



During the fore period the average daily percentage of phosphoric 

 acid excreted per man is 98; during the first preservative subperiod, 



4242 No. 84, pt 104 15 



