216 INFLUENCE OF FOOD PRESERVATIVES ON HEALTH. 



COMPARISON OF NITROGEN BALANCES. 



In order to get a general statement of the nitrogen balance during 

 the whole period of observation the average daily balances for Series 

 I, III, IV, and Y have been summarized by periods. The general 

 summary of the nitrogen tables arranges the data of all the five series 

 by periods, and from this summary the following average daily nitro- 

 gen balances are obtained, the data for Series II being omitted (see 

 Table LV, p. 306): 



Grams. 



Fore periods 0. 964 



Preservative periods 1. 020 



After periods 1. 690 



We see from the above data that during the thirty-one days embraced 

 by the fore periods the average daily nitrogen balance per man is 0.964 

 gram. During the ninety-three days of borax treatment the average 

 daily nitrogen balance is 1.02. During the thirty-five days of after 

 period the average daily nitrogen balance is 1.69. The total effect, 

 therefore, of the administration of borax upon the nitrogen balance has 

 been to decrease slightly the amount of nitrogen excreted in proportion 

 to the whole amount entering into the food. The disturbance pro- 

 duced, although slight, is perceptible. The fact that the magnitude of 

 this disturbance is increased rather than diminished during the after 

 period might be cited as evidence that the preservative is not the real 

 cause of the phenomenon observed. This, of course, must receive 

 due consideration. On the other hand, it may also be suggested that 

 the maximum effect produced by the preservative might not have 

 been felt until some days after its withdrawal from the food, and this 

 explanation of the above data is also worthy of consideration. 



PERCENTAGE ELIMINATED. 



The percentage of nitrogen eliminated in the feces and urine has 

 been calculated for each person under observation daily and by 

 periods. These data are complementary to those showing the bal- 

 ances by days and periods, which have just been given, the percent- 

 ages being perhaps somewhat more convenient for comparison. 



SERIES I. 



For the fore period, December 16-21, inclusive, the average daily 

 percentage of nitrogen eliminated in the feces and urine for the six 

 men is 87.6. (See Table XL VI.) The highest percentage eliminated 

 is found in the case of No. 6, namely, 101.2, and the lowest in the case 

 of No. 3, 76. 3. 



For the first preservative subperiod, extending from December 22 

 to December 26, inclusive, the average percentage of nitrogen elimi- 

 nated is 95.1. The highest percentage eliminated is found in the case 

 of No. 6, 108.5, and the lowest in the case of No. 5, namely, 86.7. 



