630 
Journal of Agricultural Research 
Vol. XXI, No. 9 
Table II .—Carbohydrate content of the healthy and rotted halves at the close of the 
respiration period 
Experi¬ 
ment 
No. 
Sample. 
Moisture. 
Reducing 
sugar as 
glucose." 
605 
/Control. 
Per cent . 
67.40 
3-9330 
\ Rotted. 
71-95 
4.2424 
‘ 609 
/ Control. 
68.25 
4.8709 
\ Rotted. 
73-55 
8.6419 
631 
/ Control. 
71.30 
6.4365 
\ Rotted. 
76.7O 
4-7507 
637 
/Control. 
73-50 
6.3600 
\ Rotted. 
74.60 
4.9000 
Total 
sugars as 
glucose." 
Cane 
sugar." 
Starch." 
Total loss 
of reduc¬ 
ing sugar 
equivalent 
to CO2 
evolved. 
Total 
carbo¬ 
hydrates 
as glucose 
not ac¬ 
counted 
for as CO2. 
45.880 
39-845 
196.851 
Gm . 
Gm . 
10.206 
55-3 08 
5-525 
47 - 9 r 5 
165.083 
168.541 
6 -7425 
3.9699 
13.827 
52.? i 8 
4.926 
43-967 
147.298 
166.205 
13 -! 5°9 
4.4414 
25.440 
70.800 
i 9- 6 55 
61.220 
127.260 
166.135 
8.6457 
8-0133 
19.615 
13.980 
I 53-925 
8.5258 
5-*474 
" Expressed in milligrams per gram of original wet weight 
The results of these analyses show that the starch, total sugars, and 
cane sugar are lower in the rotted than in the sound half of the potato. 
In the first two experiments the reducing sugars are increased and in 
the last two decreased. It is, of course, not possible to state from these 
experiments alone in what form the carbohydrates are utilized by 
Rhizopus tritici. Other investigations by the writers showed that glucose 
is readily utilized and cane sugar sparingly or not at all. Furthermore, 
in nutrient solutions this fungus will thrive better with boiled starch 
as a source of carbon than when cane sugar is used. On the other hand, 
raw starch in culture solutions (5) is hydrolyzed to some extent by 
R. tritici. Hawkins (9) found that certain species of Fusarium 
reduced the sucrose and reducing-sugar content of the Irish potato while 
the starch content was not altered and that in the peach the brownrot 
fungus increased the reducing sugars and the total sugars and decreased 
the cane sugar. 
It would seem from the experiments of the writers that a fairly con¬ 
stant supply of reducing sugars was maintained and that the source of 
this supply was the cane sugar and starch. 
The total amount of C0 2 evolved is shown in the last column of Table 
I, and in column 8 of Table II the reducing sugars equivalent to the 0 O 2 
output is given. The total loss of the carbohydrates (starch, cane sugar, 
and reducing sugar) as determined from the analyses is seen to be greater 
than that which is accounted for by the C 0 2 given off. In the last 
column of Table II is shown in grams the loss of carbohydrates in excess 
of that which can be accounted for by the C 0 2 output. 
What becomes of the carbohydrates can be only a matter of specula¬ 
tion. Hasselbring and Hawkins (7), in respiration work with sound 
sweet potatoes, found that the cane sugar accumulated slightly and 
