Dec, I92I] LEVINE — STUDIES ON PLANT CANCERS 521 
No. 
Normal 
Root Inoculated 
August 15, 1920 
Harvested 
October 20, 1920 
Total 
Root 
Leaf 
Total 
Without 
Gall 
Gall 
Root 
Leaf 
55 
56 
57 • • 
58 
59 
60 
61 
62 
63 
64 
65 
66 
68 
69 
70 
71 
72 
73 
74 
75 
76 
18.80 
23.50 
13.80 
12.80 
13.40 
22.05 
11.80 
37.50 
12.90 
15-30 
15.30 
11.70 
17.70 
20.10 
15.50 
15.80 
18.00 
392.50 
23.70 
8.00 
14.60 
12.00 
9.00 
8.90 
8.10 
17.35 
8.80 
27.40 
15.80 
9.50 
9.30 
II. 10 
8.30 
9.50 
19.00 
8.60 
7.30 
9.70 
255.55 
3.50 
5.80 
4>50 
7.80 
3.90 
4.00 
1.80 
3.30 
8 1^0 
3.40 
20.50 
2.70 
1.80 
3.40 
2.40 
4.00 
4.30 
4.20 
3.70 
1.45 
4.70 
99.65 
Total 
789.80 
39.49 
239.60 
11.98 
550.20 
27.51 
2,405.30 
32.94 
1,729.70 
23.69 
675.60 
9.25 
628.65 
8.61 
1,101.05 
15.08 
Discussion of Results 
The average weight of the root of the normal beet grown in fairly fertile 
soil is less than the average weight of the root of the same variety bearing 
a crown gall due to an artificial inoculation with Bacterium tumefaciens and 
grown under similar conditions. The average weight of the beets bearing 
crown galls and grown in pots filled with a garden soil and manure com- 
bination is greater than the average weight of the beets inoculated with 
Bacterium tumefaciens and grown in pots filled with sand. The average 
weight of the entire normal beet plants is greater or less than the average 
weight of the entire inoculated beet plant, depending upon the number of 
leaves on each. The leaves and crown of a normal beet plant weigh more 
than the leaves and crown of a plant of the same variety grown under 
similar conditions but whose root bears a crown gall. It is suggested that 
this difference in leaf development may be caused by interference with the 
distribution of food caused by the crown galls, although no direct evidence 
upon this question is available. 
The evidence is clear that a well nourished, vigorously growing, and 
healthy host responds to the invasion of a parasite by a hypertrophy and a 
hyperplasia which are greater than result in the case of a poorly nourished 
or feebly growing host. These results are in agreement with the obser- 
