Dec. IS, 1914 



Changes in Composition of Ripening Bananas 



199 



At the start of each experiment a current of carbon-dioxid-free air was 

 led through the desiccator for about half an hour at the rate of from i to 

 2 liters per minute, this inter\'al constituting a fore period during which 

 the carbon dioxid was not collected. The absorber was then inserted in 

 the train and the air passed through at the same rate as during the fore 

 period. A water gauge inserted between the desiccator and the Reiset 

 tube served to indicate the relative rate of flow. After an interval of 

 from one to two hours the absorption apparatus was replaced by a freshly 

 filled Reiset tube and the carbon dioxid collected for a second interval. 

 The rate of respiration was thus determined during two successive 

 intervals. In general, well-agreeing duplicates were obtained. 



The figures showing the results of the study of the rate of respiration 

 are given in Table VI. At the beginning the bananas were just on the 

 point of turning yellow and were much more active (io6 mg. of carbon 

 dioxid per kg. hour) than the green fruit used in the calorimeter studies 

 (30 mg. and 30 mg., respectively). The respiration was most intense 

 (146 mg. per kg. hour) when the rate of transformation of starch was 

 greatest. It then slowly slackened, reaching at the end 91 mg. per kg. 

 hour." As the rate of respiration of each sample analyzed was deter- 

 mined immediately before its analysis, the total amount of carbon dioxid 

 evolved during the ripening period, 3.776 per cent of the original bananas, 

 was easily estimated by a summation process from the data given in 

 Table VI. 



a In the two calonraeter studies the respiration rate of the bananas reached maxima of 150 and 200 mg per 

 kg. hour, respectively, and the respiratory activities at the end were no and 100 mg per kg hour respec- 

 tively. 



6 Grams carbon dioxid per kg. per hour. 



<^ Weight used in calculating was 1,990 gm.. three fruits having been rejected whose weight calculated to 

 the original weight was subtracted from the original weight of the sample. 



"fWcight used in calculating was r 310 gm.. otic fruit having been rejected, its weight calculated to 

 original and subtracted. 



