IOWA ACADEMY OF SCIENCES. 
77 
GERMINATION OP 
CORN AFTER BEING HEATED IN DRY OVEN FIFTEEN 
MINUTES. 
Temperature of oven. 
Percentage that came 
up. 
Average height at end of seven days. 
—Inches. 
Check 
100 
4.2 
05 
100 
3.55 
67 
100 
3 8 
69 
100 
3.6 
71 
100 
3.3.) 
73 
100 
3.8 
74.5 
100 
II. 
3.7 
Temperature of oven. 
Percentage that came 
up. 
Average height at end of eight days. 
— Inches. 
Check 
100 
6.12 
76 
80 
1 7 
76-76.5 
65 
1.8 
76.5 
65 
1.6 
77 
30 
1 
77.5 
60 
III. 
1.6 
Temperature of oven. 
Percentage that came 
up. 
Average height at end of five days. 
—Inches. 
Check 
80 
1.5 
75-76 
80 
.75 
76-77 
70 
.75 
77-78 
60 
Showed decided injury. 
78-79 
00 
Only 3 sprouted in 11 days. 
79-80 
00 
IV. 
Only 1 sprouted in 11 days. 
Temperature of oven. 
Percentage that came 
up. 
Growth. 
Check 
100 
At end of 6 days 6 inches high. 
77.5-78 
no 
At end of 6 days 40 per cent sprouted. 
78 -78.5 
00 
At end of 6 days 38 per cent sprouted. 
78.5-79 
00 
At end of 6 days none sprouted. 
V. 
Temperature of oven. 
Percentage that came 
up. 
Growth. 
77.5 
70 
Barely got above surface. 
77.75 
15 
Barely got above surface. 
78. 
00 
Only two had sprouted. 
CONCLUSIONS. 
1st. The thermal death-point for corn sinnt spores immersed 
in water for fifteen minutes is 52 ^C. . 
2d. The thermal death-point for corn smut spores heated in 
a dry oyen for fifteen minutes, 105. 5-106 ~C. 
3d. Corn is unable to push its plumule through an inch of 
soil if the seed has been immersed for fifteen minutes in water 
at 70.5^ or more. 
4th. Corn is unable to push its plumule through an inch of 
soil if the seed has been heated in a dry oven for fifteen min- 
utes at a temperature of 78 ^C or more. 
