SOIL DISINFECTION WITH HOT WATER. 9 
The object of using fresh greenhouse soil was to determine, if pos- 
sible, how much of the increased growth in plants in treated soil was 
due to the absence of the pathogenes and how much to the chemical 
or physical effects of the boiling water applied. 
For the bench experiment, soil from the previous bench experi- 
ment was used, with which was mixed a quantity of soil from the 
eelworm-infested tomato bench. 
TREATMENT OF THE SOIL. 
Four-inch pots. — Twelve 4-inch pots were filled with infested soil 
and treated as follows: Three check pots were immersed in cold 
water and three each immersed in boiling water at 98° C. for 2J, 5, 
and 10 minutes, respectively. They were allowed to dry for four 
days and were then sown to Stone tomatoes. 
This experiment was duplicated, using greenhouse soil presumably 
uninfested and three additional check pots. 
Eight-inch pots.— Twelve 8-inch pots were filled with infested soil 
and treated as follows: Three were thoroughly soaked with cold 
water and used as checks and three each were treated by the applica- 
tion of 2,000, 3,000, and 4,000 c. c. of boiling water, respectively. 
All were allowed to dry for four days, and were then sown to Stone 
tomatoes and Big Boston lettuce, one-half of each pot to each crop. 
The experiment was duplicated with greenhouse soil supposedly 
uninfested, six checks being used instead of three. 
Certain of these pots were used to determine the temperatures 
observed in the soil, the time required to raise the soil to the different 
temperatures, and the length of time the heat was maintained, the 
results of which are given in Table VI. 
Greenhouse bench. — The bench experiment was an exact repetition 
of that of Experiment Series I, except as to the quantities of boiling 
water applied, which in this case were 11,250, 22,500, and 33,750 c. c, 
respectively, for sections 1, 2, and 3. These quantities were com- 
puted as approximately equivalent to 1,000, 2,000, and 3,000 c. c. 
per 8-inch pot of soil. 
In section 3 a record of soil temperatures obtained during the 
treatment was kept, as in the case of the 8-inch pots. Two ther- 
mometers were inserted in the soil in different parts of the bench sec- 
tion to a depth of 3 to 4 inches and the temperatures recorded. 
RESULTS. 
The details of the results secured from this series of experiments 
are given in Tables III to VI in the form of germination counts, 
notes on disease occurrence and on the vigor and size of plants, and 
temperature records. The experiment was terminated on June 12, 
and notes on root infections were made as in Experiment Series I. 
