22 2 BACTElRIA IN RELATION TO PLANT DISEASES. 



that time flabby and somewhat discolored. Some hours later there was a distinct increase in the 

 size of the wilted spot. The sixth day the whole leaf -blade was affected. The rest of the plant was 

 normal. The eighth day the leaf -blade was shriveled. The ninth day the blade of i leaf below and of 

 2 above the inoculated leaf showed decided wilt. The tenth day the blade of the first leaf below had 

 changed to a lighter green in places (same color as the primary wilt). The second below was also 

 drooping, two bright green leaves above had collapsed beyond recovery, and two more further up 

 were beginning to droop. The eleventh day the plant was badly affected. Two leaves below the 

 infected one and 3 leaves above it had wilted. By the twelfth day the plant had developed an 

 advanced and very typical case of the wilt. Two leaves below the pricked one (there were no more 

 leaves on this part of the stem) and 4 above it were shriveled beyond recovery and becoming dry. 

 The one next above drooped to a slight extent and the next one very slightly. The thirteenth day 

 the plant was photographed, all the leaves being wilted at that time (see plate 16, fig. 2). The 

 fourteenth day the plant was cut to pieces and examined. Many vessels were clogged full of 

 bacteria, a portion of which when examined in water were seen to be distinctly motile. Some had a 

 darting movement half across the vessel. Most of the vessels in all the bundles were gorged with the 

 bacteria. The organism was very sticky to the touch and would string out when touched with the 

 platinum wire. Fig. 57 was drawn from a smeared cover-glass preparation of this sticky ooze stained 

 with carbol fuchsin. 



Of 6 gelatin tubes (roll-cultures) inoculated from this plant, 2 showed no growth, 2 were con- 

 taminated by a greenish liquefying organism, i by a white liquefying organism dubbed the 

 "angleworm," and i by a cadmium orange organism. Of 2 agar poured plates made from this stem, 

 I contained nothing on September 18 and i about 50 colonies of a contamination — a gray- white, 

 crenate-margined colony, wet-shining at the edge but the rest of the surface covered by a flour-like 

 coating. This latter plate was made in an unusual way, i. e., by crushing a segment of the clean stem 

 (not externally sterilized) in a tube of sterile water and transferring a loop of this fluid to the agar. 

 Three hypotheses occur as an explanation of these failures: (i) The parasite was dead in the par- 

 ticular part from which inoculations were made; (2) the organism was so viscid 

 that it did not wash off the needle or dissolve readily in the melted agar; (3) the 

 agar was too hot when inoculated, i. e., exerted a killing influence [my technique 

 was still imperfect]. 



Inoculations of September 13, 1894. 



Plants 9 and 10 were inoculated September 13, 1894, from tube 



I, September 8 (a potato culture from a cucumber fruit). The slime 



was flat, gray -white, wet-shining, in small patches on the center of the 



Fig. 57.* potato and growing slowly. It was very sticky and spun out in a fine 



thread when touched with a needle. No record of results was made or 



if made, it has been lost. 



Inoculations of September 19, 1894. 



These inoculations were made on healthy but small hothouse vines of Cucumis sativus 

 by means of needle-pricks. The infectious material was a beef -broth culture 2 days old 

 (No. I, September 17) derived from vine 2 and containing actively motile rod-shaped 

 bacteria. The needle-pricks were confined to a small part of one leaf-blade of each vine. 



(12.) The signs were so long delayed that no results were anticipated. Up to October 8 (p. m.) 

 the plant was healthy in appearance, but by 9 a. m., October 9 (the twentieth day), the inoculated 

 leaf-blade had changed color and begun to wilt. The blade and also the tip of' the petiole were 

 drooping at 2 p. m. The leaves at each side of the inoculated one were turgid. The twenty-first day 

 the pricked leaf had begun to dry and hang down, its petiole being flabby. No other leaves showed 

 any signs. The twenty-second day the next leaf below and the first one above the inoculated leaf 

 were wilted and drooping— more at i p. m., than at 9 a. m. Three days later 7 additional leaves had 

 wilted, all of them above the pricked one, making a total of 10 wilted leaves — i. e., the one pricked, 

 I below and 8 above. The twenty-seventh day the vine was brought into the laboratory. Segments, 

 including a small fruit, were preserved in alcohol. 



(13.) One leaf-blade was pricked. The plant subsequently dried up but not as a result of the 

 inoculation. 



(14.) No record. 



. , *^^?- 57-— Cover-glass preparation of B. tracheiphilus stained with carbol fuchsin. Smear made Sept. is, 1894, 

 with white ooze from cut stem of vine No. 8, which was inoculated Sept. i (plate 16, fig. 2) . Organism motile in vessels 

 X 1000. 



