1Q20] 



MAGNESS— INTERCELLULAR SPACES 



3" 



held in an oven at 30 C. A few were held also at 2 C. In all 



cases abundant aeration was provided to prevent the possibility of 



an accumulation of C0 2 in the air surrounding the fruit. A sum- 



mary of the data on the internal atmospheres in apples is given in 

 table I. 



TABLE I 



Analyses 



Temperature of 

 storage °C. 



Number of 

 determinations 



Percentage CO2 



Percentage Oa 



Percentage 

 CO.-f-Oz 



Percentage N* 

 by difference 



2 



5 

 3° 

 27 

 31 

 29 



6. 7 

 8.4 



12.2 

 17.2 

 21.4 



14.2 

 12.9 

 IO.7 



5-5 

 3-2 



20 n ^^ t 



6 



21.3 



22.9 



22.7 



24.6 



/ V ■ a 



78.7 

 77.1 



773 

 754 



II 



20 



30 





The data presented in table I require but little discussion. It 

 is apparent that the percentage of C0 2 in the gas within the tissues 

 increases markedly at the higher temperatures. At the same time 

 there is a corresponding decrease in the percentage of oxygen 

 present, the average ranging from 14. .2 per cent at 2 C. to only 

 3.2 per cent at 30 C. These data, representing averages of a 

 number of determinations, clearly indicate the marked variation 

 that may occur in the composition of gas in the tissues under 

 varying conditions of temperature. 



It is of interest to note that at the lower temperatures the total 

 percentage of oxygen plus that of carbon dioxide is about equal to 

 that of the air. At the higher temperatures, however, and in 

 association with the decreasing amounts of oxygen in the tissues, 



the 



sum of these two gases gradually increases. 



This would 



indicate that at the higher temperatures one molecule of oxygen 

 liberates more than one molecule of C0 2 . Such data accord with 

 the work of Gerber (5) , who found that in fleshy fruits stored at 

 high temperatures acids were mainly respired, and that the ratio 

 of C0 2 to 2 under these conditions was considerably superior to 

 unity. There is also the possibility that at the higher temperatures 

 a certain amount of anaerobic respiration is going on, due to the 

 relatively small amount of oxygen present. This would result in 



