558 
Journal of Agricultural Research 
Vol. V, No. 13 
DISCUSSION OF DATA 
If the results of these experiments are considered in a general way, it 
is found that the rate of starch conversion varies with the temperature. 
At 30° C. the process is rapid at first, but soon appears to approach a 
point where no further conversion takes place. At 15.5 0 , if the second 
experiment is regarded as typical, the rate of starch hydrolysis is less 
rapid, but at this temperature also the process seems to approach a state 
of completion. At 5 0 the process is distinctly retarded, but it continues 
without decrease during the period covered by the experiments. 
The rate of accumulation of cane sugar also varies with the temper¬ 
ature. At 30° the greater part of the cane sugar is formed during the 
fir9t 10 to 12 days after the roots have been severed from the vines, but 
the rate of accumulation diminishes rapidly. At 5 0 very little cane sugar 
is produced during the first 10 to 12 days, but subsequently the rate of 
accumulation is considerably increased, as if there were a lag at first in 
the formation of cane sugar at this temperature. 
The behavior of the reducing sugar is obscured by its utilization in 
respiration. It is nevertheless evident from the data presented in this 
paper and in former papers that at 30° C. the production of reducing 
sugar is sufficiently rapid to provide all that is used in respiration and 
still permit a considerable accumulation which, under normal condi¬ 
tions, is not far behind that at 5 0 . At 15.5 0 (second experiment) and 
at 5 0 there is a marked accumulation of reducing sugar at first, but at 
these temperatures, as well as at 30°, there is very little further accumu- 
ation, or even a slight subsequent loss. 
The apparent lag at first in the accumulation of cane sugar associated 
with the marked accumulation of reducing sugar at low temperatures may 
throw some light on the process of the formation of cane sugar from 
starch. In the experiments at 5 0 C. reducing sugar was obviously 
formed during the first period as a result of the conversion of starch. 
The disappearance of starch continued at the same rate during the 
second period. During this period there was, however, no further in¬ 
crease in reducing sugar, but a large increase in cane sugar. Since it is not 
likely that in the one instance reducing sugar resulted directly from the 
conversion of starch, and in the other, cane sugar, it may be assumed that 
the production of reducing sugar went on at a rate corresponding to the 
loss of starch during both periods and that the excess which was pro¬ 
duced during the second period was utilized in the formation of cane 
sugar. In this connection it is worthy of note that the concentration of 
reducing sugar always remains comparatively low. Even at low tempera¬ 
tures, at which starch transformation goes on continuously and respira¬ 
tion is reduced to a minimum, the reducing sugar content does not rise 
above 2 to 2.5 per cent. It appears, therefore, that with the exception 
of the quantity used for respiration the reducing sugar is transformed into 
cane sugar as fast as it is formed from starch. Its rate of transformation 
