REFLECTIONS ON DISEASE TREATMENT 165 
1,500 gallons of boiling water per hour. It takes 130 
hours to treat one acre of land, in the course of which 
approximately 200,000 gallons of water are applied. 
Deep Sterilization with Hot Water 
In this process the normal winter dressing of caustie 
lime is first applied to the soil. Drills are next made 
across the house and as close together as possible ; 
generally they are a foot apart and 6 inches deep. Three 
drills are treated at a time, and these are filled with 
boiling water three times. During the process extra 
heat is provided by the rapid slaking of the lime, which 
“‘ explodes ” all over the ground, and, with the repeated 
filling with boiling water, produces a temperature of 
150° F. at a depth of 9 inches. Three floodings are 
sufficient to level the soil and the next three drills are 
then filled up three times and so on. 
By this method, 180,000 gallons of boiling water are 
applied to each acre, or 37 gallons per square yard. 
Using a boiler delivering 1,500 gallons of boiling water 
per hour, and working 10 hours per day, the process takes 
12 days. 
The Boiler Tray Method 
In this method soil is heated in a shallow tray placed 
on the top of an ordinary heating boiler. ‘The tray, made 
of galvanized iron, 8 feet long, 3 feet wide, and 1 foot 
deep, is made to fit over the top pipes of an ordinary 
horticultural tubular boiler. The tiles and brickwork of 
the flues, etc., are made to fit round the tray in such a 
manner that the boiler may be used for ordinary heating 
purposes at the same time. Suitable brickwork is made 
to prevent the weight of the tray and soil being borne 
solely by the top pipes, as otherwise there is a risk of 
causing the ring joints of the castings to leak. Moist 
soil to a depth of 12 inches is placed in the trough, which 
is then covered with wood and waterproof sheeting. 
