SOIL DISINFECTION WITH HOT WATEK. 6 
TREATMENT OF THE SOIL. 
The soil was then placed in standard 4 and 8 inch unglazed earthen 
pots and in a section of a raised greenhouse bench. Inasmuch as 
the soil in different containers received different treatments, each 
series of experiments is here considered separately. 
Four-inch pots. — The 4-inch pots were treated by immersing them 
for 2J, 5, and 10 minutes, respectively, in boiling water at 98° C. 
(208°. F.). Three pots were included in each treatment, and one was 
left untreated as a check. The soil used was taken from the green- 
house bench described, but was not further infected by the addition 
of nematode-infested roots. During the immersion of the pots the 
water was kept boiling by means of two large Bunsen burners. The 
check pot was immersed for a short time in cold water. Following 
the immersion, the pots were removed and the surplus water allowed 
to drain off. They were then placed on the greenhouse bench, 
which was covered with a layer of fresh cinders, to reduce the pos- 
sibility of reinfestation with nematodes, and allowed to dry for five 
days before planting. 
This experiment was duplicated, using the same sifted soil plus 
nematode galls of tomato roots. These galls were cut up into small 
pieces, about one-third inch long, and mixed with the soil in the top 
half of the pots. 
Eight-inch pots. — The 8-inch pots were filled with the infested soil 
to within 1 to 1| inches of the top when well shaken down. Three 
pots each were then treated by applying 1,000, 2,000, and 3,000 c. c, 
respectively, of boiling water at 98° C. (208° F.). An additional 
pot was thoroughly wet down with cold water and left as a check. 
In the case of the 1,000 c. c. treatment, the boiling water was all 
applied at one time, but with the larger treatments it was added as 
rapidly as it penetrated the soil. 
As soon as the respective quantities of water were added, the pots 
were covered with newspapers to hold in the heat, and the surplus 
water was allowed to drain off. The pots were then left on the 
greenhouse bench to dry for five days previous to planting. 
This experiment was also duplicated, using sifted infested soil 
plus nematode-infested tomato roots cut up and thoroughly mixed 
with the topsoil in the pots. 
Greenhouse bench. — A portion of a greenhouse bench about 3 by 4 
feet was divided into four sections approximately 18 by 26 inches 
by means of 1-inch boards which extended to the bottom of the 
bench and about 2 inches above the surface of the soil, which was 
about 5 inches deep. The soil was the same as that used for the pot 
experiments described above, except that it was not sifted and did 
not receive additional nematode-infested tomato roots. 
