Dec, 1921] 
LEVINE STUDIES ON PLANT CANCERS 
from a neighboring lot, and the third, a combination of equal parts of garden 
soil and manure and of the loam used in the second. The fourth group 
was filled with a medium sand used for building purposes. Three seedlings 
were planted in each pot. The pots were placed in boxes, and the spaces 
between the pots were filled with hay. 1 he boxes were then placed in the 
open where they were exposed to the light all day. When the tap roots 
began to appear, the soil was gently removed from one side of each root, 
and, with a needle dipped in a culture of Bacterium tumejaciens, the root 
was pricked five to fifteen times. The soil was then returned and the plants 
were not disturbed again until the middle of October. Then they were 
carefully removed from the soil and studied. In each group of pots, some 
plants were left uninoculated to serve as controls. 
Field studies were made in three plots 12 x 25 feet each. The first two, 
"E" and "W, " consisted of soil well worked and thoroughly mixed with 
an abundance of manure. The third, "SW," consisted of a coarse sandy 
soil never used before and unfertilized. In early May, the plots "E" and 
"SW" were planted with a mixture of Early Model and Egyptian Early. 
The rows were thinned out in June, and in the latter part of July, when the 
tap roots began to appear, they were inoculated in the manner described 
above with young cultures of Bacterium tumefaciens. Each inoculated 
plant was labeled. An equally large number of uninoculated plants were 
left growing among the inoculated ones to serve as controls. The plots 
were equally well exposed to sunlight for the greater part of the day. They 
were similarly worked and watered. A considerable number of inoculated 
plants were gathered from time to time and fixed for a cytological study 
to be reported on at a later time. 
Plot "W" was sown with the Giant Mangel Wurzel seeds and treated 
as the plots "E" and *'SW" were. 
Relation of the Soil Quality to the Size and Weight of the Root 
AND OF THE CrOWN GaLL 
We may consider first the experiments in which the beets were grown 
in pots as described above. The effect of the crown gall on the total beet 
crop grown under these conditions is only suggestive since the number of 
our experiments was relatively small. The relation of the size and weight 
of the root to the size and weight of the crown gall is the point .with which 
we are specially concerned. 
In this series of experiments, as noted, a mixture of seeds of the garden 
beet varieties. Early Model and Egyptian Eaily, were grown in 48 six-inch 
pots in four different kinds of soil. In the first group, made up of 12 pots, 
the soil consisted of a mixture of manure that had previously been used 
for mushroom culture and an equal quantity of garden soil. The second 
group of pots were filled with a brown silt loam, the third group contained 
equal parts of manure and brown silt loam, and the fourth contained a 
medium sand. 
