424 Journal of Agricultural Research voi. vi, No. n 



were inoculated by pouring on the soil tap-water suspensions of B. irach- 

 eiphilus from beef-agar slants 6 days old. Of these 60 plants 24 were 

 root-pruned, and the remaining 36 were left uninjured. In this experi- 

 ment 26 strains, isolated from squash, cucumber, and cantaloupe 

 (Cucumis melo), were used, and each culture was proved to be virulent 

 by needle-puncture inoculation into the leaves of healthy cucumbers 

 of the same age and variety. The virulence tests were made about 30 

 minutes before these agar slants were used for the soil inoculations. 



The plants were under daily observation, and there were no signs of 

 wilt until April 1 1 , when one of the root-pruned plants wilted. Between 

 this date and April 19, 6 of the 24 root-pruned plants (25 per cent) and 

 8 of the 36 uninjured plants (22 per cent) wilted. Examination of the 

 stems and main roots showed the typical stringy slime in the vascular 

 system, and cultures from these roots proved the presence of B. irachei- 

 philus. 



It will be seen that in this test the percentage of wilt was about the 

 same in the root-pruned plants and in those not root-pruned. However, 

 too much weight can not be given to the results of this experiment, since 

 the cucumbers had been recently transplanted and examination of the 

 roots showed considerable eelworm injury. These wounds might, of 

 course, afford entrance for the wilt organism. 



SEED TRANSMISSION 



Ripe cucumber fruits were collected from wilted vines at Malone and 

 Constable, N. Y., on September 23, 1914. Five of the fruits from Malone 

 and one from Constable showed on cutting an abundance of the sticky 

 white ooze characteristic of this bacterial wilt, and microscopic examina- 

 tion revealed enormous numbers of typical bacteria in the vascular 

 system. The seeds were carefully preserved, and three months later 

 were planted in the greenhouse. Good germination resulted, and after 

 three months' growth no signs of wilt had occurred in any of the plants. 



In July, 191 5, a large White Spine cucumber fruit almost full grown 

 was inoculated from a pure culture of the bacterial wilt organism. The 

 fruit became infected and the wilt extended gradually throughout the 

 whole vine to which it was attached. Seeds from this fruit were pre- 

 served, and six months later a part of them were planted in the green- 

 house. Several plants came up and were under observation for four 

 weeks, but no wilt occurred. A portion of the seeds remaining were 

 used in cultural tests. The seeds were steriUzed in the usual way with 

 mercuric-chlorid solution, the seed coats removed under aseptic condi- 

 tions, and the embryos crushed in sterile bouillon from which plates were 

 poured. No clouding of the bouillon subsequently occurred, and no 

 growth from the plates. 



On August 29, 1914, a ripe cantaloupe was collected from a wilted 

 vine near Albany, N. Y. The vascular elements of the cantaloupe con- 



