19 



<TECT OF THE PRESERVATIVES UPON THE COMPOSITION OF THE FECES. 



A careful study of the effect of the preservative administered upon 

 the composition of the feces shows a slight tendency to increase the 

 amount of water therein. There is, however, no tendency of any marked 

 nature, even when the preservatives are given in large quantities, to 

 excite diarrhea. The administration of the preservative produces a 

 slight increase in the weight of dry matter in the feces. 



INFLUENCE OF THE PRESERVATIVE UPON THE METABOLISM OF 



NITROGEN. 



There is only a slight effect produced as a whole, as determined by 

 the data of experiment, upon the excretion of nitrogen. The individ- 

 ual variations are somewhat marked, showing the danger of depending 

 too positively upon data from only one or two persons. A slight tend- 

 incy is shown, however, on the part of the preservative to decrease 

 the excretion of nitrogen, which tendency becomes more marked after 

 the withdrawal of the preservatives. For instance, the average nitro- 

 gen balance of the four series of observation (excluding Series II), 

 during the fore periods is 1.009, during the preservative periods 1.12, 

 and during the after periods 1.74 grams per day. Expressed as a per- 

 centage the combined data show an excretion of 94.2 per cent of nitro- 

 gen taken in the food during the fore periods, 93.6 per cent in the pre- 

 servative periods, and 90.1 in the after periods. 



The general summary of all the experiments with borax and boric 

 acid indicates the largest elimination of nitrogen in the fore periods, an 

 intermediate amount in the preservative periods, and the smallest elim- 

 ination in the after periods. 



This relation is either produced by causes other. than the administra- 

 tion of the preservative or the effect of the preservative continues after 

 ks administration has ceased and even after the preservative itself has 

 eased to be excreted from the body. It is not impossible that such 

 an influence may be exerted. The retarding influence of the preserva- 

 ative probably increases with the length of the experiment, especially 

 in those cases in which the amount of preservative administered is pro- 

 gressively increased. When the administration of the preservative is 

 discontinued, the elimination of nitrogen is probably at the lowest point 

 (if depressed by the preservative), and yet during the first days of the 

 after period (at least while the preservative is still in the system) the 

 amount of nitrogen eliminated is probably a!s low as on the preceding 

 days. There may be a tendency of the preservative in the large amounts 

 in which it is administered to increase the formation of difficultly soluble 

 compounds of nitrogen, and by that means, if no other, retard its elim- 

 ination from the body. 



