14 
BULLETIN 1383, U. S. DEPARTMENT OF AGRICULTURE 
over the embryo; lot 3, over the endosperm, about one-eighth of an 
inch above the embryo; lot 4, over the endosperm, at the brush 
end; and lot 5, over the endosperm, on each cheek in a location 
behind the embryo. 
The five lots of each variety were then divided into three equal 
parts. One part was left untreated, one part was treated by the 
modified method, and one part was treated by the single-bath 
method. In the latter method the treatment at 48° C. for 1 hour 
and 50 minutes was selected. Immediately after treatment on 
February 8, 1924, the seed was spread and left to dry for six days 
at room temperature. The untreated and treated grain was then 
sown in soil in greenhouse flats, and the seedlings were counted 30 
days later. All of the varieties reacted similarly. Averaged results 
from all varieties are presented in Table 8. 
Table 8. — Percentages of germination of hand-threshed seed wheat untreated or 
treated with hot water, as specified, when the seed coats were unbroken or broken 
over the embryo or over the part of the endosperm described, as shown by green- 
house tests in 192 4 
[The percentages shown are the average results from the five varieties, Currell, Forward, Fultz, Purple- 
straw, and Stoner] 
Percentage of germination when seed coats were— 
Treatment of the seed 
broken 
Broken over endosperm 
Broken , 
embryo 
Over 
brush 
end 
On each 
cheek 
behind 
embryo 
96 
94 
94 
94 ! 92 
78 
26 88 
93 
67 
84 
88 
49 
Treated by the single-bath method at 48° C. for 1 
78 
Table 8 shows (1) that the amount of injury from treatment by 
the single-bath and by the modified method is determined by the 
condition of the seed coat, and (2) that when the seed coats are broken 
as noted the single-bath treatment is less injurious to germination 
than the modified treatment. The practical significance of this 
fact becomes apparent in view of the finding by Nobbe (12), Kuhn 
(9), Schellenberg (14), Von Tubeuf (16), Volkart (17), Burmester 
(3), Wallden (18), Hurd (7), Tapke (15), and others that machine 
threshing damages seed coats. In view of the data presented in 
Table 8 it seems safe to assume, therefore, that seed treated by the 
single-bath method will suffer less injury to germination than seed 
treated by the modified hot-water method. Nobbe (12), Volkart 
(17), Wallden (18), and others also have pointed out that the amount 
of cracking of seed coats by the threshing machine varies from year 
to year, and that it is more prevalent in dry years. Schellenberg 
(if) has shown that machine threshing usually damages the larger 
kernels. It is therefore evident that the lesser amount of germina- 
tion injury caused by the single-bath method may vary from year to 
year and with the variety used. When the seed coats were unbroken, 
as shown in Table 8, the percentage of germination of seed treated 
bv the modified hot-water method was as high as that of seed treated 
