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Journal of Agricultural Research 
Vol. V, No. 16 
If a vigorous culture on suitable media (prune-juice agar or corn-meal 
agar) was sealed with sealing wax no pycnidia were produced, even 
though comparison tubes unsealed produced pycnidia in abundance. 
Sealed tubes which had remained without pycnidia for two weeks had 
the sealing wax removed, and the pycnidium formation was slowly 
inaugurated. Corn broth in capsules, if covered with a small bell or if 
placed in a battery jar with a tight-fitting ground-glass cover, produced 
scanty mycelial growth but no pycnidia. 
Tests for aerotropism were made with spores in melted agar. Melted 
agar was heavily sown with spores of the organism. Some tubes were 
prepared with a lighter seeding. Small drops of these agars were placed 
on sterile slides and sterile cover glasses pressed down upon them. Other 
preparations were made with the cover glass tilted, as in Beijerinck's 
(1893) well-known experiments. These slides were put away in a moist 
chamber for 24 hours at ordinary room temperatures. The results of 
these tests were extremely interesting. 
Where the spores were numerous those at the center of the preparation 
showed no evidences of germination other than a slight swelling. Out¬ 
side the center zone germination became more and more evident. About 
5 mm. from the edge of the cover glass the germ tubes were found to be 
10 to 50 times the length of the spore. At the edge of the cover glass 
the germ tubes had extended outward nearly a half of a millimeter. 
Where the spores were fewer in number the germination in the center 
sometimes proceeded to the extension of a short germ tube. There was 
no evidence of a definite tropism toward the border of the cover glass, 
but frequently the same spore would have sent out two germ tubes from 
opposite sides, one growing toward the edge of the glass, the other grow¬ 
ing inward. Then it was noticed that the sprout growing in the medium 
with the richer oxygen supply was from 4 to 10 times the length of the 
other germ tube. 
Where a clump of spores occurred about halfway from the center to 
the edge of the cover glass, those spores near the edge swelled strongly 
and put out germ tubes, while spores of the same clump, situated nearer 
the center, remained dormant, or at least swelled only slightly. The 
repression of germination in these spores seemed to be related to the 
scanty oxygen supply, and for this there was strong competition. 
A series of flasks of different sizes was prepared with filter-paper cones, 
wet with 5 c. c. of distilled water. These were autoclaved and inocu¬ 
lated with a spore suspension. Immediately after inoculation the cotton 
plug was pushed slightly down the neck of the flask and the flasks were 
sealed with melted paraffin. The flasks were set in a window in even, 
diffuse illumination. After a month the reading shown in Table IX 
was obtained. 
