LITERATURE ON BUNT OF WHEAT. 13 
Bedford, and Mackay (332), who recommended treating bunt-free 
seed with a strong solution of copper sulphate as a protection against 
such wind-distributed spores. The idea is next found in the same 
"paper in which Maddox (255) presented his evidence of blossom infec- 
tion of the loose smuts in 1896. Maddox here notes that bunt is very 
jiable to appear in a fallow field lying to the lee of threshing opera- 
- tions. 
Appel (/4) relates a specific instance of such infection. A machine 
_ threshing a bunty lot of wheat was so situated that the dust was blown 
across a part of a field that was sown soon afterwards, and the crop 
was about half bunt in this part and bunt free in another part that 
was not exposed to the wind-blown dust. 
PHYSIOLOGIC RESPONSE OF SPORES OF TILLETIA TO TEMPERATURE. 
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Hofimann (/64) investigated the thermolethal points of several 
_ of the Ustilaginex, but did not include Tilletia in his experiments. 
- Schindler (336), on the contrary, confined his work to TwQlletia 
caries Tul. He found that spores were somewhat injured by an 
_ exposure to 65° C. of dry heat for a period of two hours, but that the 
absolute death point for a 2-hour exposure was between 95° and 
_ 100° C.; that when placed in water for two hours at 40° C., they were © 
somewhat injured; and that the death point lay between 45° and 
50° C. He states that an exposure of —16° C. of dry cold for two 
_ hours was not injurious and that the spores were not killed by out- 
_ door exposure in the soil from December 5 to January 16. During 
_ this period the average daily minimum temperature was —8.5° C. 
and the average maximum ~—1.3° C. According to Jensen, a 5- 
- minute exposure to damp heat ranging from 52.5° to 60° C. is fatal 
_ to the spores of Tilletia. Kiihn states that most of the spores are 
_ killed by a 5-minute bath at 52.5° C. According to Kirchner (207), 
_ they are all killed within five minutes at 55° and 56° C. 
— Tubeuf (372, 574) germinated spores in water that had been sub- 
_ jected to a temperature of 37.5° to 38° C. for 24 hours. There was, 
_ however, a tendency to abnormality in the germination. He obtained 
no germination from those exposed for three days to a temperature of 
_ 39° to 40.5° C. 
Volkart (384) found that spores of Tilletia would not germinate 
at and above a temperature of 30° C. but were uninjured at that 
_ temperature and germinated perfectly in four days when transferred 
to suitable temperatures. 
CONTROL OF BUNT. 
HISTORY OF SEED TREATMENT FOR THE PREVENTION OF BUNT. 
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Seed treatment for the prevention of bunt, by one method or 
another, has been practiced nearly three centuries. Before the true 
~ nature of the disease was known many of the more intelligent farmers 
_ conceived methods of seed treatment on the theory that the seed 
_ needed a stimulus to enable it to resist the disease, hence the use of 
_ fermenting animal manures. With the idea of the infective nature 
of smut came the use of toxins. The origin of the use of copper 
sulphate has been generally credited to Kiihn, but he makes no claim 
to originality and credits it to Prévost, who in turn passes it back to 
Tessier. The fact is, it is of still earlier origin, for it was recommended 
