26 
Journal of Agricultural Research 
Vol. XXVII, No. I 
into bottle C. If this is done, the whole equipment will be under atmos¬ 
pheric pressure at all times. 
The oxygen consumption was measured by measuring the volume of 
water in bottle C and subtracting 3 per cent from this volume as an 
estimation of the quantity of oxygen absorbed in the water. C 0 2 
dissolved in the KOH solution was determined by the double titration 
method as used by Gore ( j 3) , phenolphthalein and methyl orange being 
the indicators used. 
Analyses of the contained air in desiccator D showed an accumulation 
of C0 2 of less than 1 per cent by volume even when held at high tem¬ 
peratures and with rapid respiration going on. The apparatus can be 
used at any temperature by substituting NaCl or CaCl 2 solutions for 
the water at temperatures below 32 0 F. 
It is essential that the temperature be kept constant during any run. 
If the temperature rises, the atmosphere in D and C will expand, driving 
the water back from C and even with a possible loss of 0 2 through B. 
If the temperature drops, the lowering of the volume of the contained 
atmosphere will result in a greater volume of water in C and apparent 
greater 0 2 consumption. Fluctuation should not be greater than i° C. 
RESPIRATION OF WINESAP APPLES AT 32 0 F. (o° C.) 
The data for the respiration of Winesap apples at32° F. are presented 
in Table IV. Oxygen determinations for the first series were lost, but 
C 0 2 output was measured, and both C 0 2 and 0 2 output were measured 
for the second series. 
Table IV .—Respiration of Winesap apples at 32 0 F. ( 0° C.) 
Ex¬ 
peri¬ 
ment 
No. 
Description 
of fruit. 
1 Normalfruits months 
in storage; check. 
2 Fruit coated with 
paraffin. 
3 j Fruit coated with oil, 
; light coating. 
4 | Fruit coated with oil, 
very heavy coating. 
Weight 
of 
fruit. 
Run 
No. 
i 
Length 
of run. 
Kilo¬ 
gram 
hours. 
Weight 
CO2. 
CO2 
per 
kilo¬ 
gram 
hour. 
Volume 
CO2 per 
kilo¬ 
gram 
hour. 
Volume 
O2 per 
kilo¬ 
gram 
hour. 
Respir¬ 
atory 
ratio 
CO2. 
O2 
Grains. 
i 
! 
Hours. 
Mgm. 
Mgm . 
Cc. 
Cc- 
2.873 
1 
358 ^ 
1,030.0 
2,167. 5 
2.10 
1.07 
2 
381K 
1,096.0 
2,007.1 
1.83 
-93 
1 .02 
0.91 
2,907 
1 
358 
1,040.7 
1,807. 7 
1. 74 
.89 
2 
381M 
1,109.0 
1,625.9 
1.47 
•75 
•93 
.81 
2,822 
1 
357 K 
1,008.9 
i, 74 S -4 
i- 73 
.88 
2 
38iJ4 
1,076. 6 
1,623.3 
i- 5 i 
•77 
•97 
•79 
2,801 
1 
I , OOO. O 
1,183. 6 
1. 18 
. 60 
OD i 
381K 
1,068.6 
1,188.6 
1.11 
•56 
All of the fruit used in experiments 1 to 4 was closely comparable 
except for the treatments received. It is at once apparent that respira¬ 
tion was markedly reduced by the coatings which the fruit in experiments 
2,3, and 4 received. Light oil coating and paraffin coating both resulted 
in a marked decrease in C 0 2 output as compared with the control, or un¬ 
treated, fruit. Furthermore, the fact is developed that in the case of these 
fruits the C0 2 output was not limited by the oxygen supply, for in the 
coated fruit there was a greater consumption of oxygen per unit of 
C0 2 output than in the case of the control fruit. This is shown by com¬ 
paring the respiration ratio, obtained by dividing the volume of C0 2 per 
unit time and weight of fruit by the volume of 0 2 absorbed. The heavily 
oiled fruit showed an even greater decrease in C 0 2 output than did the 
lightly oiled fruit. Unfortunately, the oxygen absorption record was 
lost for these heavily coated apples. 
