830 
Journal of Agricultural Research 
Vol.XXI.No.ii 
and four tubers gave no organisms in any of the four quarters. This 
makes 69 tubers, or 46 per cent of the lot, which gave identical results 
from the four quarters of each tuber. Forty-six others, or about 31 
per cent, gave only one organism from a part of the quarters, varying 
from one to three, but not from all of the four quarters, the other quarter 
or quarters yielding no organism. There is thus a total of 77 per cent 
of the tubers which did not give more than one organism from each 
tuber. Thirty-four tubers, or about 23 per cent, gave two separate 
organisms, and one tuber gave three separate organisms from different 
quarters of the same tuber. 
Tabus II. —Organisms isolated from the stem end of the four longitudinal quarters of 
150 Up-to-Date potato tubers harvested in igiy from hills badly wilted with V erticillium 
albo-atrum 
Number of tubers with the four quarters of the inner vascular 
region at the stem end discolored as follows: 
Number of quarters yielding or- 
organisms. 
4 browned. 
3 browned, 1 yellowed. 
3 browned, 1 not dis¬ 
colored. 
j 2 browned, 2 yellowed. 
2 browned, 1 yellowed, 
1 not discolored. 
2 browned, 2 not dis¬ 
colored. 
1 browned, 3 yellowed. 
1 browned, 2 yellowed, 
1 not discolored. 
1 browned, 1 yellowed, 
2 not discolored. 
4 yellowed. 
3 yellowed, x not dis¬ 
colored. 
2 yellowed, 2 not dis¬ 
colored. 
1 yellowed, 3 not dis¬ 
colored. 
4 not discolored. 
Total. 
6 
6 
2 
1 
x 
5 
1 
64 
3 V. albo-atrum t x miscellaneous fungi. 
1 
1 
13 
29 
1 
ia 
1 
a V. albo-atrum, i F. oxysporum, i 
a V. albo-atrum, i F. oxysporum, i 
1 
a V. albo-atrum, a miscellaneousfungi. 
a V. albo-atrum, i miscellaneousfungi, 
t none. 
4 
3 
1 
1 
x 
1 
1 
10 
2 V. albo-atrum, a none. 
1 
1 
2 
1 
6 
r 
1 V. albo-atrum, a F. oxysporum , i 
none. 
1 
X 
1 V. albo-atrum, i F. oxysporum, a 
none. 
X 
1 
x 
t V .albo-atrum, 3 miscellaneonsfiingi. 
1 
1 V. albo-atrum, 2 miscellaneousfungi, 
1 
1 
x 
4 
x 
1 
a 
x 
x miscellaneous fnngi, 3 none. 
a 
2 
4 none... 
4 
4 
Totals. 
54 
13 
24 
7 
8 
3 
4 
4 
X 
11 
5 
1 
3 
12 
150 
Table II shows five tubers from which both Verticillium albo-atrum 
and Fusarium oxysporum were isolated in cultures from different quar¬ 
ters. The cultures from one of these tubers are shown in Plate 141, B. 
This offers a possible explanation of some otherwise confusing results 
secured during the course of this investigation. For instance, in a few 
cases F. oxysporum was isolated from seed potatoes which when planted 
in clean soil gave rise to plants that wilted from attacks of V. albo-atrum . 
In cases of this kind the latter fungus may also have been present in 
