258 INFLUENCE OF FOOD PRESERVATIVES ON HEALTH. 



here given, but it was desired to make the report as full as possible and include as 

 far as practicable all of the results obtained. 



Great care must be taken to distinguish days on which the sample of feces was 

 lost and days on which no movement of the bowels occurred. ID. the latter case no 

 substance was lost, as the excrement would naturally be collected on a later date. 

 An illustration of this is given under No. 2, for December 18, page 261. On this date 

 no movement occurred, -and yet it was included in the number of days on which 

 feces are collected and analyzed; that is, the sum of the nitrogen in the feces 

 for No. 2 during the fore period from December 16 to December 21, inclusive, 

 was 8.080 grams. Since no sample was lost, the number of grams given is divided 

 by 6 to obtain the average weight of nitrogen per day eliminated in the feces. 



In order to bring together and average the results for all the men for each series 

 and express them as a unit they were collected in summaries. The summary of the 

 nitrogen data obtained in Series I is given on page 266. Here under each man the 

 sums of each period are given, first, for the days on which both urine and feces were 

 collected and analyzed (figures not inclosed either in brackets or in parentheses); 

 second, for the days on which feces were lost, but urine was analyzed (figures inclosed 

 in parentheses); and third, for the days on which urine was lost, but the feces were 

 analyzed (figures inclosed in brackets). 



The totals for all men for each period were obtained by adding together, first, the 

 figures not inclosed in either brackets or parentheses; second, the figures inclosed in 

 parentheses, and adding to them the figures not inclosed in either brackets or paren- 

 theses for those men for whom no figures in parentheses are given; third, by adding 

 together all figures inclosed in brackets and adding to them all figures not inclosed 

 in either brackets or parentheses for those men for whom no figures in brackets are 

 given. To illustrate, in the summary for the fore period for Series I (p. 266), the 

 number of grams of nitrogen in the food of all men for all days on which both feces 

 and urine were saved and examined amounted to 566.765 grams. This sum was 

 obtained by adding the following figures: 94.948, 89.778, 115.501, 84.465, 101.744, 

 80.329. 



The number of grams of nitrogen in the food for those days on which feces were 

 all recovered and analyzed was found by adding together all of the figures given 

 above with the exception of 94.948 and 89.778 and adding to this result the figures 

 expressed in brackets, that is, 113.226 and 105.085. 



The number of grams of nitrogen in the food for all days on which the urine was 

 recovered and analyzed was found by adding together the figures given above for 

 those days on which both urine and feces were recovered, with the exception of 

 84.465, and adding to that sum the number of grams of nitrogen in the food of No. 4 

 for all days on which the urine alone was saved and analyzed, that is, 101.641. 



In order to determine the average amount of nitrogen per day in the food for all days 

 on which both urine and feces were recovered and analyzed it is necessary to turn 

 to the individual balance sheets and count the days and use the number thus 

 obtained to divide into the total number of grams in the food for those days. By 

 referring to the individual balance sheets we note that both urine and feces were 

 recovered and analyzed in the fore period for the following number of days: No. 1, 

 five days; No. 2, five days; No. 3, six days; No. 4, five days; No. 5, six days; No. 6, 

 six days, making a total of thirty-three days. Now, dividing 566.765 grams (that is, 

 the amount of nitrogen in the food for all days on which the urine and feces were 

 entirely recovered and analyzed) by this number of days, we have the result 17.17; 

 that is, the average number of grams of nitrogen in the food for each man for each 

 day of this period. 



In the same way the number of days "in the fore period on which the feces were 

 collected and analyzed was: No. 1, six days; No. 2, six days; No. 3, six days; No. 4, 



