116 BuTLER: SUGAR IN TUBERS OF SOLANUM TUBEROSUM 
germinating tubers is greatly influenced by the milieu in which 
germination takes place. Potatoes germinating at a relatively 
low temperature contain more sugar than potatoes germinating 
at relatively high temperatures, and potatoes germinating in soil 
contain more sugar than those germinating in a cellar. Again, 
the distribution of sugar in potatoes germinating in a cellar, for 
instance, is irregular. All these facts clearly indicate that the 
metabolism of germination is not concerned primarily in the 
distribution or degree of accumulation of sugar.* I will give a few 
examples in illustration. 
Conditions favorable for germination are not necessarily 
favorable for the accumulation of sugar. For instance, on the 
26th of April, 1912, I examined a number of Early Ohio potatoes, 
and they contained as a rule no sugar (PLATE 2, FIG. 6) though 
the sprouts were replete with it. A sample of these potatoes was 
placed in the ice compartment of an ice chest for 20 days, after 
which the potatoes composing it contained sugar as indicated in 
FIG. 2,5. At the same time similar potatoes from the cellar con- 
tained sugar as indicated in FIG. 1 and 4. It is worthy of note 
that the potatoes stored in the ice chamber (Fic. 2, 5) resembled 
very closely the potatoes shown in FIG. 7, as regards distribution 
of the accumulated sugar. The distribution of sugar illustrated 
by FIG. 7 was rather common in stored potatoes during March, 
1911, which stored potatoes had been at no time subjected to a 
temperature below 6° C. It is therefore clear that the low tem- 
perature had not induced irregularities in metabolism. 
A glance at the plate will also force upon one the conclusion 
that the degree of germination has no effect upon the distribution 
of sugar. Neither is there any connection between presence or 
absence of sugar in the cortex with corresponding changes in the 
medulla. The medulla may contain sugar even in large amounts 
and the cortex give no reaction for it (FIG. 3, 7); again the cortex 
may contain sugar and the medulla be free from it (FIG. 1), though 
such cases appear to be rarer than the former; again the cortex 
* The distribution of sugar in potatoes can be followed by boiling thin slices of 
the tubers in Fehling’s solution for a few minutes, when traces of sugar will be indi- 
cated by a yellow coloration and an abundance by a red coloration, various shades 
of orange indicating intermediate amounts. 
