BUTLER: SUGAR IN TUBERS OF SOLANUM TUBEROSUM 117 
may contain sugar in large amounts near the suber and be almost 
free from it near the line of the medulla, which in turn may be 
more or less replete with it. Conditions illustrated in FIG. 2, 5, 9 
are also not uncommon. 
The distribution of sugar in germinating potatoes, considered 
with reference to the budding eyes, is also worthy of note. If 
one cuts longitudinal slices through potatoes in which the apical 
buds alone have sprouted he will find almost invariably that there 
is less sugar in the tubers immediately below the shoots than 
elsewhere. The conditions illustrated in FIG. 2, 5, 7, in which 
the medulla colors orange in Fehling’s solution except for small 
areas beneath the insertion of the shoots and around the buds, 
may be also observed. 
Qualitative tests having indicated that in germinating potatoes 
sugar occurred in less amounts near the apices than toward the 
bases and having also given indications that the bases were 
usually richer than the middle portions, I thought it would be well 
to have these results confirmed by quantitative analyses. The 
results obtained were as follows. 
TABLE IV 
DISTRIBUTION OF SUGAR IN GERMINATING POTATOES 
Percentage reducing sugar in potatoes 
Remarks 
Variety Apical zone Middle zone Basal zone 
Gas a sg 8) se eee nee ane 0.12 .28 59 Single tuber. 
Composite 
Hatly ONG 25 63 shies None 15 42 sample of 
ro tubers. 
BarhrOMn. 62304 saa ce Trace 35 88 Single tuber. 
Flashy OM 666 oa ccs ees Trace .46 50 Single tuber 
Eany Gale oro. os ners None 35 85 Sin le tuber 
SALTS ORG 255 6 ee oe 0.17 -59 7 Single tuber. 
TABLE Iv confirms entirely the conclusions deducible from 
qualitative tests. Potatoes contain little or no sugar near their 
apices, sometimes nearly as much in their middle as in their basal 
portions, and sometimes much more towards the base than in the 
middle. It may be observed that Miiller-Thurgau* found that 
resting potatoes were richer in sugar at the base than at the apex, 
and we have seen that this is generally true also of germinating 
potatoes. 
* Loc. cit. p. 763. 
