244 BACTERIA IN RELATION TO PLANT DISEASES. 



The culture used in making these inoculations had the following history : 



(i) Sept. I. Typical diseased cucumber vine brought in from Anacostia, D. C. 



(2) Sept. I. Vine No. 2, inoculated with white sticky slime direct from above plant. First signsthe fourth day. 



(3) Sept. 17. Beef-broth-culture direct from the interior of vine 2 . 



(4) Sept. 2 7 . Slant meat extract peptone agar streak culture from 3 . 



(5) Oct. 17. Potato-cylinder inoculated from one colony in No. 4. 



(6) Nov. 1 2 . Potato-cylinder from 5 . 



(7) Nov. 15. Potato cylinder from 6. 



(8) Nov. 20. Streak on a slant tube of unfiltered alkaline potato-agar. 



(9) Dec. 3. Potato-broth tube No. 2 from 8. 



(10) Dec. 6. Potato cylinder No. 5 made from 9. 



(11) Dec. ID. Plants inoculated from Tube 5, December 6, which now contained the same wet-shining, white, 

 motile, and very sticky bacillus with which I started on September i . 



On December 20 the squashes were in 4-inch pots and growing satisfactorily. 



Inoculations of January 3, 1895. 



Potatoes, hyacinths, squashes, tomatoes, muskmelons, pear and cucumber were 

 inoculated in the hothouse with a white, sticky schizomycete from a slant meat extract 

 peptone agar culture of December 28 (cucumber-strain). The culture was examined the 

 day the inoculations were made and found to consist of bacilli, a large proportion of which 

 were motile. Great care was taken to avoid contamination, to use the bacteria as soon as 

 taken from the surface of the agar, and to make the needle-punctures as small as possible. 

 My method in this instance was to put a little of the white, sticky mass on the surface of 

 the plant (leaf or stem) and then prick it in elsewhere, touching the needle tip to the slime 

 each time before inserting it. Each plant received many punctures. In case of the squashes 

 extra pains was taken to select full grown or nearly full grown leaves, and to make many 

 very small needle-punctures, so as to prevent the bacteria from drying out and to secure 

 their introduction into suitable tissues. Up to this time the inoculations into squashes 

 had been unsuccessful. The temperature in the hothouse was 68° F. For the past month 

 the day temperature had been about 70° F. 



(98.) Potato {Solanum tuberosum). A very thrifty plant, growing in a 4-inch pot, was pricked 

 on a terminal leaflet and in the middle part of the stem. 



No result. 



(99.) Potato. This plant was growing in a 4-inch pot, was 14 inches high and very thrifty. It 

 was pricked on one end-leaflet and in the middle portion of the stem. 



The eighteenth day the vine was examined for bacteria. The top had been shriveled for a week, 

 and all the leaves had fallen. The rest of the stem, including the pricked parts, was normal. No 

 bacteria were found in the vessels of the stem between the pricked part and the shriveled tip. 



(100.) Hyacinth {Hyacinthus orientalis) . The leaves of this plant were two inches long at the 

 time of inoculation. The flower scape had not yet elongated but the buds were visible. It was a 

 very healthy plant. Many pricks were made on the apical part of four difi'erent leaves. 



No result. 



(loi.) Hubbard Squash {Cucurhita sp.). Many pricks were made on the apical portion of the 

 blade of the sixth leaf of a small thrifty vine. 



The twenty-fifth day the plant was brought into the laboratory for examination. Most of the 

 leaves had fallen except those toward the apex where they were normal but small. The stem was 

 green and long. It was examined in several places but not a trace of bacteria was found. The 

 plant was crowded in a, 4-inch pot. 



(102.) Hubbard Squash. A comparatively large, thrifty plant was inoculated. Many pricks 

 were made on the apical portion of the blade of the eleventh leaf. This leaf was about 6 inches from 

 the apex of the vine. 



The twenty-sixth day the plant was brought into the laboratory and examined. It was at this 

 time 123 cm. long. Only the upper 30 cm. were leafy. The stem was green and turgid throughout. 

 The stem was examined microscopically in three places — ^toward the base, in the middle, and toward 

 the top. There was not a trace of bacteria. The plant had been kept in too small a pot. 



(103.) Red Hyacinth {Hyacinthus orientalis). This plant bore leaves only about 2 inches long 

 and the flower-stalk had not yet elongated. The plant was a very thrifty one. Many pricks were 

 made on the apical portion of each of four leaves. 



No result. 



