Aug. 15, 1914 
Oxidases in Potatoes 
377 
Table; I .—Relation of the total weight of the shoots of the whole hills , as well as of the 
single shoots , to the age of the potato plants 
Series No. 
Date of col¬ 
lection. 
Age. 
Total 
weight of 
shoots. 
Num¬ 
ber of 
hills. 
Mean total 
weight of 
shoots 
per hill. 
Num¬ 
ber of 
shoots. 
Mean 
weight of 
shoots. 
Days. 
Grams. 
Grams. 
Grams. 
I. 
July 9 
29 
84 
c 
17 
D 
2. 
July 10 
3 ° 
102 
7 
15 
17 
6 
4 .. 
July 11 
3 i 
IS© 
8 
19 
22 
6.8 
6. 
July 12 
3 2 
108 
8 
13*5 
19 
5 - 7 
9 . 
July 14 
34 
222 
15 
15 
3 = 
6.9 
10. 
July 15 
35 
297 
9 
33 
23 
12. 9 
12. 
July 31 
19 
75 
7 
11 
40 
1.9 
14 . 
July 31 
19 
100 
6 
17 
41 
2.4 
15 . 
Aug. 1 
20 
170 
6 
28 
64 
2. 7 
18. 
Aug. 2 
60 
36 ° 
1 
360 
3 
120 
21. 
Aug. 4 
62 
750 
2 
375 
4 
188 
24. 
Aug. 8 
66 
680 
1 
680 
4 
170 
26. 
Aug. 9 
67 
368 
1 
368 
1 
368 
2 9 . 
Aug. 11 
30 
365 
5 
73 
44 
8-3 
3 2 . 
Aug. 21 
40 
500 
1 
5 °° 
7 
71.4 
35 . 
Aug. 29 
88 
350 
1 
35 o 
1 
350 
38 . 
Sept. 8 
98 
375 
1 
375 
1 
375 
In order to present these data more clearly, they were plotted as shown 
in figure 1. The ages of the plants are measured off on the abscissae and 
the weight of the shoots on the ordinates. The continuous line corre¬ 
sponds to the development of the plants (the total weight of the shoots 
of one hill), and the broken line corresponds to the mean rate of devel¬ 
opment of all of the single shoots of one hill. 
The irregularities of the curve representing the growth of the shoots of 
a whole hill are apparently due to variations in the number of stalks 
contained therein. This becomes strikingly apparent from the smooth¬ 
ness of the curve representing the growth of single stalks. With prac¬ 
tically no interruption this curve shows a gradual increase in size until 
the sixty-seventh day is reached, growth of the stalks apparently stopping 
at that point. The curve from this point on is practically a straight line. 
OXIDASES OF HEALTHY POTATO PLANTS 
In order to be able to compare the oxidase activities of diseased potato 
plants with healthy ones at the same stage of development, it was essen¬ 
tial to establish the oxidase content of healthy material at all stages of 
development. Such a study on normal plants is also of general physio¬ 
logical interest. While the excellent work of Palladin (1906) and his 
school has shown that the respiration of plants takes place in stages cor¬ 
responding to several distinct respiratory enzyms, they have made no 
measurements of the oxidizing power of these respiratory enzyms. More¬ 
over, working with frozen wheat seedlings and those not frozen and with 
etiolated leaves of Vicia faba and leaves of Plectogyne japonic a , they con- 
