jan. 13, 1923 Forcing the Germination of Freshly Harvested Wheat 89 
three days after treatment, against 56 per cent in three days and 64 
per cent in five days in the control. The only lot which failed to germi¬ 
nate well after treatment was a lot of scarcely ripe wheat freshly harvested 
from the standing plants and carrying nearly 30 per cent (wet-weight 
basis) of moisture. This lot germinated 16 per cent in six days after 
treatment and failed to germinate at all in the control. Probably if 
comparable lots of oats and barley had been treated in the same way 
the germination would have been no better. 
Simply removing the hulls from poorly germinating lots of oats and 
barley slightly increased their germination. 
Scratching the embryo had much more effect than cutting off the distal 
end, inducing practically complete germination in two or three days 
of all lots thus treated except the one lot of wheat which was least affected 
by cutting of the distal end. This germinated 86 per cent in six days, 
while the control failed to germinate at all. The tendency to decay was 
much less than when the endosperms were removed, apparently on 
account of germicidal properties of the wounded embryos. 
2 . REMOVAL or THE COAT STRUCTURES WITH CONCENTRATED SULPHURIC ACID 
This treatment also has been found very successful with dormant 
Johnson grass seed ( ig ). In this investigation it was used only with 
wheat. It is classed as a mechanical treatment because its effect appar¬ 
ently depends entirely upon the removal or weakening of the coat stru c- 
tures over the embryo. The grain was immersed in the concentrated 
acid for from 30 seconds to 5 minutes, washed in sodium-bicarbonate 
solution, rubbed free from as much as possible of the disintegrated 
tegumentary structures, and finally washed for about half an hour in 
running water. The first part of the coat to be visibly affected was 
that over the radicle, which became slightly charred in 30 seconds. 
After 3 minutes’ treatment nearly the entire coverings rubbed off readily 
except over the edges of the scutellum and over the distal end of the 
caryopsis. Even after 5 minutes these parts were not wholly bared. 
The most rapid and complete germination was secured after 3 to 5 
minutes’ treatment, but the acceleration was quite noticeable when the 
treatments lasted only 30 seconds, therefore only slightly weakening the 
coat but probably effecting its permeability to a marked degree. This 
was the most effective of all the mechanical treatments, causing complete 
and prompt germination of the most resistant sample; but it is almost 
as tedious as the others and entails great danger of subsequent decay. 
In all probability, the effect of all mechanical treatments here reported 
depends fundamentally upon the same cause, which may be either (1) 
relieving the axial parts of the embryo of some inhibiting substance by 
diffusion outward, or (2) an increase in respiration or an alteration in its 
nature by allowing more ready exchange of oxygen and respiratory 
products, or (3) a more obscure “stimulus” to the living protoplasm. 
Possibly, also, a similar stimulation of the epithelial layer of the scutellum 
plays at least a secondary part when the endosperm end of the caryopsis 
is removed or the scutellum is wounded by scratching. In this connec¬ 
tion, it should be said that simply rubbing off the thin membrane which 
remained over the embryo of barley after the imbibed naked caryopses 
were removed from the scales also induced quick and complete germina¬ 
tion of the most troublesome sample. The embryos were injured, 
however, sufficiently to cause some of the elongating coleoptiles to curve 
