290 
AMERICAN JOURNAL OF BOTANY • 
[Vol. io, 
The average amount of glucose found after each of the three procedures 
was: for (a) none; for (b) trace (?); and for (c) 33.3 mg. respectively. This 
indicates that phloridzin does not reduce copper either in the direct reduction 
or after inversion procedures, but that it is quantitatively hydrolyzed by 
the “complete-inversion” treatment. 
Relative Behavior of Maltose and Phloridzin with Mixtures of other Sugars. 
Two definite mixtures of pure chemicals were made up: one contained 
maltose with glucose and sucrose; the other, phloridzin with glucose and 
sucrose. Analyses were run on each for directly reducing sugars, total 
sugars after inversion, and those after complete inversion. It was found 
that in these mixtures all the sugars and phloridzin could be recovered 
quantitatively by the regular procedure of sugar analysis, providing, of 
course, allowance was made for some destruction of glucose and fructose 
during the severe “complete-inversion” treatment. 4 Also, it should be 
kept in mind that the increased reducing power after complete inversion 
is multiplied by 2.42 in calculating phloridzin, and by 2.32 5 in calculating 
maltose. It seems apparent from the results of these analyses that the 
method suggested by Darwin and Acton is quite as applicable for the 
quantitative determination of phloridzin as for that of maltose. 
Application of the Darwin and Acton Method to the Analysis of Apple 
Tissue. The maltose method described was temporarily made an integral 
part of the analytical procedure in the analysis of 48 samples of summer 
shoots of apple, collected in connection with the regular horticultural 
experiments of the Station. These samples were of two varieties, Spitzen- 
burg and Grimes, and had been collected at intervals from June 24 to 
August 29. 
The increases in reducing power after “complete inversion” are pre¬ 
sented in table 1, calculated both as phloridzin and as maltose. The 
values on each date are averages of duplicate determinations on four 
Table i. Percentages of Maltose or Phloridzin in Apple Shoots 
Date of Collection 
Increased Reducing Power 
Calculated as: 
Maltose (as 
Reported by 
Mitra) 
Phloridzin 
Maltose 
June 24. 
4-34 
377 
2.63 
July 14. 
2.91 
2-53 
2.98 
August 29. 
2.82 
. 2.45 
2-37 
4 The solutions subjected to the complete inversion contained a total of about 1 percent 
glucose and fructose after hydrolysis. Under these conditions, the amount destroyed by 
acid could safely be considered less than 4 percent of the total, although in one instance 7.8 
percent was believed to have thus disappeared. 
6 The factor 2.1 seems to conform more closely with the reducing power of maltose 
under the conditions of analysis prescribed by the American A. O. A. C. 
