COBB'S DISEASE OF SUGAR-CANE. 33 



shows any discoloration in the interior except in the immediate vicinity of the needle-pricks. The 

 discoloration has not extended cither up or down into any of the internodes. 



C alcdonia Queen. 



No. 52. This is a fairly good cane. It is about 8 feet in length. The basal leaves are brown 

 and shriveled, but the upper ones are all perfectly healthy. The stem is about i .5 inches in diameter 

 at the base. There is no discoloration in the stem except in the inoculated internode, where it does 

 not extend at all from the needle-pricks. The cane seems to be perfectly healthy throughout its 

 entire length. 



No. 53. This cane is about 5 feet in length and has much the same general appearance as the 

 preceding one. The cane is perfectly healthy throughout. 



No. 54. Presents the same external appearance as the two preceding canes and is about the 

 same size. Running through the four internodes above the point of inoculation is a small number of 

 yellow bundles. Whether or not these contain bacteria could not be determined with the hand-lens. 

 The cane has made a very good growth and is about the same size as the uninoculated canes of this 

 variety. 



LABORATORY NOTE. The section taken from this cane showed a distinct yellow ooze from a 

 small group of bundles in the center of the stem. This was made up of masses of bacteria. Plates 

 were poured from this stem. 



No. 55. This cane is about the same size as the others and presents the same general appear- 

 ance. In three of the basal internodes there are a few red bundles, but these soon run out, not extend- 

 ing as high as the point of inoculation. The only other discoloration in the stem is in the inoculated 

 internode. Presents exactly the same character as that in check. Is simply a local oxidation. 



Crystalina. 



No. $6*. This is a cane which has made a fairly good growth, although it is of a rather small 

 diameter. It is perfectly healthy throughout its entire length. 



No. 57*. This is an exceedingly small cane. It is very sickly looking. Although the inocu- 

 lation was made in very young internodes, it has given no result. The stunting of the cane may be 

 due to the fact that some of the pricks pierced the terminal bud. 



Jamaica. 



No. 58*. This is a cane about 6 feet in length. The basal leaves are all dead. This is probably 

 due to the fact that they have been strangled by the wire with which the label was fastened on. The 

 majority of the upper leaves are beginning to brown at the tips, while the terminal bud is entirely 

 dead and the surrounding leaves are covered with fungi. The cane internally is perfectly healthy 

 throughout. 



No. 59*. This cane is about 7 feet long and seems to be perfectly healthy, with the exception of 

 the uppermost leaves enveloping the terminal bud, which are dead and brown. This injury, however, 

 is due to the ventilating iron. Perfectly healthy throughout internally. 



No. 60*. This cane is much like No. 59, except that it is not quite as long. Externally it seems 

 to be very healthy. The tissue of this cane is perfectly healthy throughout. 



Check. The check presents exactly the same appearance as all the other canes of this variety. 



General Note. The distribution of the bacteria from the point of inoculation in the 

 diseased canes can not be judged accurately, however, in any of these cases, as the needle- 

 pricks were made through many leaf-sheaths as well as through the stem. In all cases 

 where bacteria were found in the stem the organism used was of the same parentage. At 

 the time of inoculation it was known that there were in our cultures at least two kinds of 

 yellow organisms, some of the stock tubes behaving differently from the others. 



Cane-plants 40, 42, and 46, inoculated June 22, 1904, and cut September 27, 1904, 

 yielded from the interior of the stems numerous colonies of Bacterium vascuUtrum in prac- 

 tically pure culture (14 poured plates). I do not find any record respecting No. 54. 



SERIES VI. 1905. 

 Inoculations of Sugar-cine in Hot-house No. 4. 



On May 22, 1905, two assistants, Miss Florence Hedges and Miss Harriett Thomson, 

 were set at work inoculating sugar-cane with Cobb's organism. I planned to inoculate 

 several shoots on every other row, 2 leaves to be selected and 30 or 40 punctures to be made 



