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. 



Material used for inoculation. 



Connecticut Broadleaf. 



June 



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 Y/ater. 



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. 



affected with mosaic 

 disease on May 9. 



6 affected with mosaic 



disease on May g. 

 All healthy on May 9. 



6 affected with mosaic 

 disease on May 26. 



o affected with mosaic 

 disease on May 26-28. 

 affected with mosaic 

 disease on May 28. 



affected with mosaic 

 disease on May 28. 



All healthy on May 28. 



10 affected with mosaic 

 disease on June 6. 



affected with mosaic 

 disease on June 8. 



All healthy on June 8. 



4 affected with mosaic 

 disease on June 10. 



affected with 

 disease on Jur 



