1x6 Journal of Agricultural Research voi.xxi, No.* 
and other varieties has prevented further experiments on the relation of 
morphology of the heads to the susceptibility of the seeds to fungicides. 
These experiments on semipermeability of barley seed coverings were 
made with more concentrated solutions than are used in farm practice. 
It seemed desirable to determine the effect of the recommended strength, 
i pound to 4 gallons, on different varieties, after the usual immersion of 
about five minutes. The varieties found to germinate normally after 
this treatment were Tennessee Winter, Mariout, Beldi, Turkestan, and 
Coast. Mariout,. Beldi, and Coast showed slight retardation and root 
injury, but this would not be serious in soil germinations. However, the 
Nepal (White Hull-less) variety was more seriously injured, with retarded 
plumules, stunted roots, and a germination of only 80 per cent against a 
control germinating ioo per cent. 
LIMITATIONS AND VARIATIONS IN SEMIPERMEABILITY OF SEED 
COATS OF WHEAT 
Wheat seeds are injured and killed by prolonged exposure to copper- 
sulphate solutions in spite of the fact that their testas are reported with¬ 
out exception to be semipermeable membranes. Brown (3) says that 
grains of Hordeum vulgare were not injured by a 3-day exposure to a 5 
per cent solution of copper sulphate, but we have found no sample of 
either wheat or barley which would stand an exposure of even 1 day in 
a 1-pound to 4-gallon solution without injury, while death resulted in 
many cases. Reference to Table V will show the endurance of one of 
our best wheat samples in a saturated solution. It was found in this 
as well as in many repetitions that while hand-thrashed seed may be 
uninjured after 6 hours in this solution, injury is decided after 8 hours, 
and but a small percentage of seedlings, all retarded or deformed, are ob¬ 
tained from seed exposed for 16 or 24 hours. In many cases, extreme 
injury was produced after an exposure of only 6 hours. The data in 
Table X illustrate the variations and the limitation of the phenomenon 
of semipermeability in wheat. 
To the data in Table X should be added the fact that no germination 
was obtained in thrashed Turkestan (see Table IX for exception), 
Tennessee Winter, Beldi, Nepal, and Mariout barleys after immersions of 
six hours in saturated copper-sulphate solutions, although barley kernels 
of these types always are reported as inclosed in semipermeable mem¬ 
branes. We shall exclude barley, however, from this discussion, as it 
has been shown that the nature of the abscission of the kernel may have 
something to do with its permeability. 
