220 INFLUENCE OF FOOD PRESERVATIVES ON HEALTH. 



over that recovered in the excreta is given as a positive number, while 

 any excess of phosphoric acid and phosphorus in the excreta over that 

 in the food is given as a negative quantity. 



In the daily balances, as was the case with the nitrogen, there was 

 no attempt made to secure an absolute separation in the feces of the 

 food eaten on any given occasion by the administration of some color- 

 ing matter like powdered charcoal. For that reason the variations in 

 the daily balances are often exaggerated, inasmuch as the quantities 

 of excreta, especially of feces, vary greatly from day to day. In pe- 

 riods extending over four or five days, however, these variations would 

 be practically compensatory, so that the expression of the total balance 

 for each period is approximately correct. Attention should be called, 

 however, as in the preceding cases, to the fact that owing to the great 

 difficulty of marking with absolute certainty the excretory processes 

 some slight differences or errors are to be expected. These, however, 

 are again eliminated from the averages of the periods by combining 

 them all into a single expression. 



SERIES I. 



In the fore period the average daily balance per man is found to 

 be 0.081 gram. The largest positive balance for the fore period is 

 2.14, and the largest negative balance for the period 0.768. 



In the first preservative subperiod, extending from December 22 to 

 December 26, inclusive, the average daity balance for the whole period 

 is 0.182. The only positive balances during this whole period are 

 found in the cases of Nos. 1 and 2, namely, 0.438 and 0.258, respec- 

 tively, and the largest negative balance is found for No. 4, namely, 

 2.407. 



In the second subperiod, extending from December 27 to December 

 30, inclusive, the average daily balance for the period is 0.289. The 

 largest positive balance for the period is found in the case of No. 5, 

 namely, 1.968, and there is no negative balance. 



In the third subperiod, extending from December 31 to January 3, 

 inclusive, the average daily balance is 0.031. The largest positive 

 balance for the period is found in the case of No. 5, 1.786, and the 

 largest negative balance in the case of No. 1, 2.989. 



For the entire preservative period, from December 22 to January 

 3, inclusive, the average daily balance is 0.029. The largest positive 

 balance for this period in any case is found in No. 5, namely, 3.255, 

 and the largest negative balance in the case of No. 1, 0.873. 



In the after period, extending from' January 4 to January 13, inclu- 

 sive, the average daily balance is 0.029. The largest positive balance 

 during this period is found in the case of No. 5, namely, 3.494, and 

 the largest negative balance in the case of No. 6, 2.124. 



In this series as a whole it is seen that the administration of the 



