BROWN ROT OP SOLANACEAE. 



I8 5 



Result. Very successful: The first signs appeared on the seventh to ninth day, beginning as brown streaks in many 



bitten places. On August 4, 49 separate infections were counted. 

 August 14. Twelve plants were inoculated: Potato, tomato, cucumber, and heliotrope. Potato culture No. 1, August 



12, direct from the interior of plant No. 16, inoculated July 1 1, was used. 

 Result. Very successful on potato ; less so on tomato. On cucumber a swollen stem appeared (the pricked internode) ; 



this contained living (motile) bacteria on September 8. Heliotrope (?). 

 A ugust 17. In this experiment 8 plants were inoculated : Portulaca oleraceae, tomato, Physalis ph iladelph ica, heliotrope, 



Citcurbita foetidissima, Eleusine indica, Ricinus communis, and Vigna catjang. Many pricks were made in 



each plant, introducing potato culture No. 1, August 12, which was direct from interior of plant No. 16, 



inoculated July 11. The tomato was punctured on a thrifty shoot near the top. 

 Result. Very successful on Physalis philadelpkica, the first 



sign appearing about the tenth day. For effect 



on Physalis see figs. 93, 94. The infection of 



tomato was slow no wilt up to August 28. The 



other plants failed to contract the disease. 

 August 20. Ten inoculations were made on this date, 



using Solatium carolinense for the experiment. 



Many needle-pricks carried in large quantities 



of the bacterial culture (tube No. 1, August 12, 



as above), some of the pricks being made into 



leaves, others into the upper part of rather 



woody stems. 

 Result. All failed. Perhaps the inoculations were made 



too late in the season. The stems were woody. 

 September 9. Nine plants, part tomato, part potato, were 



inoculated from a fluid culture made directly 



from the swollen cucumber stem of August 14. 



Large numbers of bacteria were introduced by 



means of many needle-pricks. 

 Result. Negative. No records after September 21. 



Possibly the wrong organism was isolated the 



method is not commendable. 



Fig. 92.' 



Fig. 93. t 



September 16. Six inoculations were made on potato, from cultures Nos. 1 and 2, September 14, from Nos. 1 and 3, 



August 29, which clouded after heating 10 minutes at 51 C. (culture descended from egg-plant from 



Charleston, S. C). 

 Result. Failed. 

 Summer of 1901 {before July 19). Ten plants, part tomato, part potato, were inoculated. Many needle-pricks were 



made, introducing a pure culture from the interior of a tomato stem from South Carolina (descendant of 



poured-plate colony). 

 Result. Very successful. All contracted the disease. 



*Fig. 92. A single pitted vessel of Solatium nigrum, plant 34, occupied by Bacterium solanaccarum as the result of 

 a pure culture inoculation made some inches above and 1 3 days previous ; two unoccupied spiral vessels at the right. 



fFiG. 93. Cross-section of small part of the stem of Physalis Philadelphia!, showing bacteria in the spiral and 

 pitted vessels, and the beginning of a small cavity; epidermis at top and pith at bottom of the figure. Bacteria in the 

 cavity more abundant and with denser stain than is here shown. Plant No. 57 inoculated with Bacterium solanaccarum 

 August 17, 1896; collected and fixed in strong alcohol September 23. Drawn with the Abbe camera from a section cut 

 on the microtome and stained with carbol-fuchsin. Slide i2o(*. Crystal-sand not present. (For a longitudinal 

 section see fig. 94.) 



