252 
Journal of Agricultural Research 
Vol. V, No. 6 
ovules. A thin, sharp scalpel heated to redness was used for cutting 
away the ovary wall, so that possible infection of any portion of the 
placental tissues from the ovary wall itself was avoided. Table I shows 
the occurrence of virus in the placental structure and ovules of mosaic- 
diseased plants. 
Table! I .—Occurrence of virus in the placental structure and ovules of tobacco plants 
affected with the mosaic disease 
Date of 
inocula¬ 
tion. 
Number of 
plants. 
Variety. 
Material used for inoculation. 
Effect. 
1914- 
Apr, 23 
23 
23 
May 18 
18 
18 
18 
18 
28 
28 
28 
June 2 
2 
10 . 
Connecticut Broadleaf. 
10 . 
10 (control) -. 
10. 
Maryland Mammoth.. 
10 . . 
10.. 
.do . 
10. . . 
711 (con trot).. 
.do . 
ro (control 1 ).. 
.do. 
.do. 
.do. 
Sap of portions of placental col¬ 
umn and immature ovules of 
green capsules from plants 
affected with mosaic disease. 
These portions were macer¬ 
ated in a mortar with clean 
tap water. 
Sap of green leaves from same 
plants. 
Sap of green placentas and 
ovules from a healthy plant 
and macerated with tap water. 
Sap of macerated placentas and 
immature ovules of large, 
green capsules of plants af¬ 
fected with mosaic disease. 
Sap of ovaries entire from the 
same plants. 
Thin paste obtained by grind¬ 
ing in a mortar with a small 
quantity of tap water the 
white and brownish imma¬ 
ture seeds of two capsules 
from plants affected with 
mosaic disease. These seeds 
were scraped very carefully 
from the placental column. 
Sap of two placentas alone, 
from which the ovules were 
removed in the preceding test. 
Sap of immature seeds and pla¬ 
centas obtained from a 
healthy plant and ground 
with tap water. 
Macerated placentas and im¬ 
mature seeds of green cap¬ 
sules from plant A, affected 
with mosaic disease. 
Thoroughly mature, loose seeds 
from dried, brown, matured 
capsules of the same plant. A, 
were poured from the capsules 
into a mortar and ground to a 
thin paste with tap water. 
Macerated placentas and imma¬ 
ture seeds of green capsules 
from a healthy plant, mixed 
and ground in a mortar with 
dried mature seeds from the 
same plant. A small quan¬ 
tity of tap water was added 
to obtain a thin paste. 
Macerated white immature 
ovules carefully removed from 
the spongy, succulent pla¬ 
centas of green capsules of 
plants affected with mosaic 
disease and mixed with tap 
water to form a thin paste. 
Sap of leaves from the same 
plants affected with mosaic 
disease used in the preceding 
test. 
8 affected with mosaic 
disease on May 9. 
6 affected with mosaic 
disease on May 9. 
All healthy on May 9. 
6 affected with mosaic 
disease on May 26. 
10 affected with mosaic 
disease on May 26-28. 
4 affected with mosaic 
disease on May 28. 
7 affected with mosaic 
disease on May 28. 
All healthy on May 28. 
10 affected with mosaic 
disease on June 6. 
3 affected with mosaic 
disease on June 8. 
All healthy on June 8. 
4 affected with mosaic 
disease on June 10. 
10 affected with mosaic 
disease on June 10. 
