894 
Journal of Agricultural Research 
Vol. XXXI, No. 9 
Tests of the earliest samples by this treatment gave negative 
results, because most of the seeds were broken or crushed, but in 
the second tests 16.5 per cent germination was obtained in 40 days 
compared with only 11.3 per cent in the checks. Parallel samples 
with tips cut gave 20 per cent in the same period. But though 
germination was hastened by this means, the seed thus treated 
eventually gave a lower test than the untreated because of mechan¬ 
ical injury. 
This shows that it may be entirely feasible to increase the rate of 
germination by scarification, provided suitable machinery is avail¬ 
able. Though the perfection of such machinery is beyond the prov¬ 
ince of the present project, a modified type of barley pearling machine 
is suggested as suitable for this purpose. In this machine the grain 
is scarified between a perforated outside steel casting and q,n inside 
revolving carborundum wheel. For white-pine seed it would be 
necessary to substitute a fleece-lined sheepskin for the steel casting 
so as not to crush the seed. The process of scarifying white-pine 
seed, however, is more complicated tnan rice or barley, because very 
little pressure can be used to force the seed against the abrasing 
surface, and because the resin will clog the machine very quickly. 
A series of treatments with coarse and fine needles was tried later, 
the chief purpose being to determine whether or not germination 
could be hastened by blowing the seed against a bank of needles. 
No machine was made, but the seeds were punctured by the needles 
as they lay on the blotter. The needles were prevented from pene¬ 
trating deeper than through the seed coat by surrounding the tip 
with sealing wax. The bank of needles was made by setting them 
in a piece of paper similar to pins stuck in a folded strip of paper 
and rolled compactly and solidified by sealing wax. This bank 
made 32 points of needles within a circle one-fourth inch in diameter. 
By this treatment the seed was injured, presumably by mechanical 
impact, for only one sample of those treated showed any germination, 
and this only 5 per cent m 40 days. 
EXPOSURE TO LOW TEMPERATURES 
Additional experiments in soaking and freezing the seed weie 
made during the winter of 1916 in order to try the mechanical effect 
of the water in freezing and thawing and of exposure to low tem¬ 
peratures for a longer period in air and snow. This work was under¬ 
taken largely on the strength of the excellent results recorded by 
Pittauer 4 in stimulating germination of Pinus strobus. With dry 
freezing and 24 hours’ soaking after the freezing, he obtained 75 
per cent germination in 28 days, and with snow freezing he obtained 
56 per cent, with only 17 and 18 per cent for the untreated samples. 
The Priest River experiments, covered in Table III embraced 10 
separate groups of the same seed which were divided into three main 
divisions as follows: Groups A to D exposed to freezing in the air, 
some soaked and others not; Groups E to H, soaked and unsoaked, 
frozen in the snow; and Group I, untreated check. 
4 Pittauer, G. Aber den einfluss verschiedener belichtung und extremer temperaturen 
auf den verlauf der keimung forstlichen saatGutes. Centbl. Gesam. Forstw. 38: 157-172, 213-224, 
illus. 1912. 
