Plants as Affected by Fungous Parasites. 167 
prevented by treating the seed with a solution of certain 
chemicals or with hot water. Of the former, sulfate of cop- 
per (copper sulfate, blue vitriol, bluestone) has been most 
used, and unquestionably destroys the spores of the smuts, 
but it has generally been found to more or less injure the 
germination of the seed. 
325. The Hot-Water Treatment has proved fully as 
successful as the preceding method in disinfecting the seed, 
without affecting its vitality. This treatment consists in 
immersing the seed for ten minutes in water at a temper- 
ature of 132° F. For treating a quantity of seed, some 
special provisions are necessary, as it is somewhat difficult 
to bring every seed in contact with the water at the proper 
temperature. Provide two large vessels, as two kettles over 
a fire, or two boilers over a cook stove,—one to contain 
warm water (110-120° F.), the other to contain scalding water 
(132-133°F.). Place a reliable thermometer in the hot-water 
vessel that the temperature may be watched. The warm 
water is used to warm the seed, preparatory to dipping it in 
the hot water. Without this precaution, it will be difficult 
to maintain the temperature of the latter. The seed is 
placed in a covered basket, preferably of wire cloth, in 
quantity not exceeding one-eighth of the volume of the 
water, and the basket should be but partially filled. Im- 
merse the basket several times in the warm water a moment 
at a time, giving it a rotary motion in order to bring every 
seed in contact with the water. Then plunge it into the hot 
water and repeat the immersions as before, carefully watch- 
ing the thermometer in the meantime. Should the temper- 
ature fall below 132°, cautiously add water of a still higher 
temperature; and if it rises above this point, add cold water. 
