Nov. 8,1915 
Distribution of Virus of Mosaic Disease 
253 
Table I .—Occurrence of virus in the placental structure and ovules of tobacco plants 
affected with the mosaic disease —Continued 
Date of 
inocula¬ 
tion. 
Number of • 
plants. 
Variety. 
Material used for inoculation. 
Effect. 
1914- 
June 2 
2 
2 
June 4 
4 
4 
4 
4 
5 
5 
5 
10 
Maryland Mammoth.. 
10.do. 
10 (control)...do. 
10. 
10 
do. 
do. 
10 
10. 
10 (control) 
do, 
do, 
do, 
10. 
10. 
10 (control) 
do, 
do, 
do, 
Thin paste obtained by grind¬ 
ing with tap water in a mor¬ 
tar thoroughly dry, loose, 
ripened seeds from matured 
capsules of plants affected 
with mosaic disease. 
Same macerated material used 
as in preceding test. 
Paste obtained by grinding to¬ 
gether white immature ovules 
from green capsules and dry, 
loose, ripe seeds from healthy 
plants. Small quantity of 
tap water added to thin the 
paste. 
Thin paste obtained by grind¬ 
ing with tap water loose, dry, 
thoroughly ripened seeds of 
capsules from plants affected 
with mosaic disease. 
Sap of green leaves from the 
plants in the preceding test. 
Paste obtained by grinding and 
thinning with tap water dry, 
loose, ripe seeds from cap¬ 
sules of plant B affected with 
mosaic disease. 
Thin paste obtained by grind¬ 
ing with tap water the nearly 
mature, light brown seeds 
from ripening capsules of the 
same plant B affected with 
mosaic disease. In this test 
the capsules selected were 
still green and the placental 
column succulent and full. 
The seeds, which were firm 
and brownish in color, still 
adhered to the surface of the 
placenta. 
Paste obtained by macerating 
in a mortar with tap water 
dry, loose seeds, nearly ma¬ 
tured seeds, and leaves of 
healthy plants. 
Paste obtained by macerating 
with tap water the loose, dry 
seeds from ripening capsules 
of plants affected with mosaic 
disease. These seeds were 
mature, but the placental 
column was still succulent, 
although beginning to dry 
and shrink somewhat. 
Macerated placentas from 
which the seed in the preced¬ 
ing test was removed. Small 
quantity of tap water added 
to obtain a thin paste. 
Paste obtained by macerating 
with tap water in a mortar 
the dry, loose seeds and pla¬ 
centas of capsules obtained 
from healthy plants. 
4 affected with mosaic 
disease on June 10. 
2 affected with mosaic 
disease on June 10. 
All healthy on June 10. 
7 affected with mosaic 
disease on June 10. 
10 affected with mosaic 
disease on June 10. 
1 affected with mosaic 
disease on June 10. 
3 affected with mosaic 
disease on June 10. 
All healthy on June 10. 
2 affected with mosaic 
disease on June n. 
8 affected with mosaic 
disease on June 11 
and 12. 
All healthy on June n 
and 12. 
Earlier experiments 1 have shown that the roots, the apparently healthy 
lower leaves, and the corollas of plants affected with the mosaic disease 
sooner or later carry the virus of the disease. More recently experi¬ 
ments have been carried out to determine whether the virus is present 
1 Allard, H, A. Mosaic disease of tobacco. U. S. Dept. Agr. Bui. 40, p. 1&-19. 1914. 
