Respiration Experiments with Sweet Potatoes 



511 



the end of Table I is given the gain or loss of reducing sugar, calculated 

 from the analytical data, and the glucose equivalent of the total carbon 

 dioxid generated during each experiment, as actually determined. The 

 percentages of reducing sugar in the sweet potatoes at the end of each 

 experiment, without correction for changes in water content, were as 

 follows: First experiment, 1.24 per cent; second, 1.22 per cent; third, 

 1.39 per cent; fourth, 0.91 per cent; fifth, 0.71 per cent; sixth, 0.67 

 per cent; seventh, 0.69 per cent. The experiments themselves will be 

 described individuallv. 



Table I. — Composition and carbon-dioxid output of sweet potatoes at different times of 



the year 



Experiment i. — In this experiment 3,576.5 gm. of sweet potatoes 

 were used. These were dug on October 20. The experiment was 

 begun on the following day and continued until November 5. During 

 that period the cane-sugar content rose from 1.60 to 3.95 per cent and 

 the invert-sugar content from 0.94 to 1.23 per cent. The respiration 

 rose somewhat during the first half of the period and then fell to a 

 nearly uniform rate of approximately 28 mgm. per kilogram per hour. 

 The rise at first, which was observed in nearly all the other experi- 

 ments also, may in part be attributed to the rise of the temperature of 

 12572°— 15 2 



