25 
A Bacterial Disease oe Alealea 
jjjinis, n. sp. obtained from an infected stem. For comparison With in¬ 
oculations not specially protected against dessication, this pot was co\ered 
with a bell jar, the opening in the top being stoppered with a cotton plug. 
Circulation of air was possible yet there was a moist, if not satuiated, 
atmosphere surrounding the plant all the time. By June 18th., the 
scraped areas were blackened and a microscopic examination of this tissue 
showed the characteristic milky cloud and swarms of bacteiia. 
Pot No. 2.—Each of four stems was inoculated by ten needle pricks 
with a 48 hour agar culture of Ps. medicaginis, n. sp. This pot was also 
covered with a bell jar as described above. By June 18th, each needle 
prick showed a dark brown zone 1 mm. wide surrounding the point of 
infection. A microscopic examination of the tissue from this zone showed 
clouds of motile bacteria. 
Pot No. 3.—Four stems were inoculated in the same manner as those 
of Pot No. 1, but they were not covered with a bell jar. The plant was 
sprayed with sterile water once a day for the first three days after in¬ 
oculation. By June 18th., the stems were blackened and exhibited the 
characteristic phenomena under the microscope. The diseased condition 
of the stems was much more typical than in those which were covered 
with the bell jar. 
• p 0 t No. 4. —Four stems were inoculated in the same manner as those 
of Pot No. 2, but they were not covered with a bell jar. They weie 
sprayed with sterile water once a day for the first three days after inocu¬ 
lation. On June 18th., there was a brown area surrounding each needle 
prick and a microscopic examination of the discolored tissue showed 
swarms of motile bacteria. The gross appearance of the diseased parts 
was more typical than in the plant covered with a bell jar. 
Pot No. 5.—Four stems were scarified and inoculated with a 4S 
hour culture of P’s. medicaginis, n. sp. isolated from a diseased leaf. The 
plant was covered with a bell jar. The stems were blackened by June 
18th., but they were not as typical as those which were left uncovered. 
Pot No. 6.—Four stems were inoculated by needle pricks with a B 
hour culture of Ps. medicaginis, n. sp. isolated from a diseased leaf. The 
plant was covered with a bell jar. June 18th., the disease was eviden 
from the blackened areas around each needle prick, but it was not as 
typical as in those stems which were not covered. 
Pot No. 7.—Four stems were inoculated in the same manner as Pot 
No. 5 but were exposed to the air and sprayed with sterile water. . By 
June 18th the disease was apparent by the blackened stems and a micro¬ 
scopic examination showed swarms of bacteria coming from the tissue 
and a milky cloud surrounding the whole; more typical than stems under 
bell jar. 
Pot No. 8._Four stems were inoculated in the same manner as Pot 
No 6 but were exposed to air and sprayed with sterile water. June 18th. 
there’were dark brown areas surrounding each puncture; very typical; 
microscopic examinations characteristic. 
Plant Inoculations of June 7, 1909. 
Cultures used were isolated June 1, 1909. 
Pot No 9.—Each of four stems was scarified and inoculated with a 
48 hour culture from a yellow colony isolated from a black stem By 
June 18th the stem was slightly yellow and shiny but probably nothing 
more than the result of the scraping; nothing typical had developed, 
there was no sign of any growth of the germ and no evidence of an> 
discolored or diseased tissue. Microscopic examination failed to show 
the presence of bacteria and consequently this germ was consideied as 
not responsible for the trouble. 
Pot No. 10. _Each of four stems was scarified and inoculated with 
a 48 hour culture from an orange colony, isolated from a diseased stem. 
