Dec, 1921] 
LEVINE — STUDIES ON PLANT CANCERS 
area of 300 sq. ft. each. The first, " E," had been used during three previous 
seasons for root crops. The soil was well worked and abundantly treated 
with thoroughly rotted manure. The plot *'SW" had never been used 
for a crop. It consisted of filled-in land. The soil was coarse and made 
up chiefly of coarse sand. No fertilizer was used on this plot. Beginning 
August 4 to 15, 1920, three hundred roots in each plot were inoculated with 
young cultures of Bacterium tumefaciens and labeled. A large number of 
beet roots growing among the inoculated plants were left undisturbed to 
serve as controls. 
Fig. 3. A portion of plot "E" with the garden beet, one month after inoculating the 
root with Bacterium tumefaciens. The soil was well fertilized, and cultivated. 
A difference in the size of the plants in the plots "E" and "SW" ap- 
peared very early. Figure 3 shows a portion of plot "E." The leaves are 
not only larger but more numerous. The rows appear to be indistinct 
. owing to the fact that the leaves cover the ground. The plants in the plot 
at the time this picture was made had been inoculated one month. The 
difference between plots ''E" and "SW" was even more pronounced at 
the time the crop was harvested. 
Figure 4 shows part of the plot "SW" with the poor soil. The plants 
