2 2S 



BACTERIA IX RELATION TO PLANT DISEASES. 



tur.,'id. (The third down was wantin.i; except the base of the petiole.) The next morning all the tiny 

 leaves at the tip (bevond the second leaf up) had collapsed. By 5 P-m. of the same day the wilted 

 leaves had begun to shrivel. The fourth down was still turgid. The fourteenth day the fourth leaf 

 had lost most of its turgor. The petiole (if the pricked leaf was still green but it was flabby nearly 

 to the base. The blades of the first and second leaves below had shriveled, also those of all the leaves 

 above the pricked i)ne. The upper part of the vine was now removed for examination and cultures. 

 The vessels were f(jund to be full of the bacillus which strung out in fine gummy threads from the 

 cut surface of the stem wdien a needle-tip was touched to it and withdraw-n. The bacteria were 

 exceedingly abundant and the inner tissues were considerably broken down. The organism was cul- 

 tivated from this portion of the vine at different heights, inoculations being made frr>m the stem intr) 

 potato-broth from which a pure culture of Bacillus trachnphilus was subsequently obtained on 

 steamed potatoes. 



The fifteenth da>- the fifth leaf down was flabby. The twent>--ninth day this plant was removed 

 togetlier with the f)tlier old cucumber \'ines, to make room for squashes. Dry material was saved 

 from this \ine for the herbarium. X futile search was made in it for spores of the bacillus. 



(26.) The fifth leaf from the tip was pricked manv times in one of the side lobes. At 10 a.m., 



October ", i there were no 



but bv i'' 30'" p.m. of the same day the pricked lobe had wflted. The 

 first signs appeared, therefore, m this case at the end of the sixth day, the inoculations having been 

 made in the afternoon. B\- noon of the seventh day the wilt and change of cfjlor had made marked 

 progress in the i^rieked lobe and that portion of the'latter in which the wilt first appeared had dried 

 out. The temperature in the hothouse when this observation was made was 80° F. The following 

 dav (;, to 4 p.m. ) the whole leaf-blade was flabb\'. The pricked portion was dry-wrinkled, the petiole 



Fig. 60.* 



turgid. There was no further change until noon of the tenth day. Then the petiole of the pricked 

 leaf was slighth' flabby at the apex but still green. The blade was turning brownish on the pricked 

 side. The nearest leaf to each side was turgid. At 4 p.m. the following day, the first leaf below had 

 fullv collapsed althr>ugh turgid at 10 a.m. The second leaf abo\'e was still turgid. (The first leaf 

 above was wanting, onh- the base of the petiole remaining.) The upper part of the vine hung down 

 in such a wav that the lower (collapsed) leaf was uppermost. The morning of the twelfth da>- the 

 petiok of the first leaf below the pricked one was flabby. ^\.n obser\ation made at 5 p.m. showed no 

 further changi . The morning iif the f(iurteenth da\- after inr)Culation the blade vl the pricked leaf 

 was brown and dry-shriveled throughout. The petiole was still green and it was flabbv onlv at the 

 tip. The second, third, and fourth leaf down were flabby as was also the petiole of the second 

 leaf. The blades of the lifth and sixth leaves below (all that remained) were flabbv and shriveled 

 inclmlin^ llic fxiinlcs. This latter seemed anomalous. The petiole of the llrst leaf below was flabby 

 and shriveled to its base althougli still green. It was in a much worse condition than the pricked leaf. 

 Here wi probably have to take into account the smallness of the pot and the age of the vine, the 

 lower leaves being weaker than the others. The twent3'-ninth (hiy the plant was pulled up to make 

 room for squash vines. A portion of it was sa\ed dry for the herbariimi. Unavailing search was 

 made in it for spores of the bacillus. 



(27.) The seventh leaf from the tip was pricked many times in the center eif the lamina. There 

 werenosignsuntilthemorningof ( (etober ', i (si days). Thenthe i)ricked leaf was wilted in a V-shaped 

 area opening outward from the prii ks to the apex of the leaf. In the afternoon the condition was 

 that shown in fig. 60. The apix was drooping. The rest of the leaf was normal. The following noon, 



*Vir,. 60 '— B:i(trrial will at 4 p. ni,, Oct. ,u . "H ^i" inm. ulated leaf of cucuinlnT plant No. 27. For condition 20 

 hours later, m-c lii;. 61. Leaf |iritl<ed 1 )it. i'5, i9o_|. I'irst signs of wilt (ilarlcer .shaded part) morning of Oct. 31. 

 Drawn by Theodore Holm. 



