OCCURRENCE OF THE DISEASE ON OTHER PALMS. 153 



tiniioiis on one side from top to })ottom, and their extent at the base 

 was undoubtedly the cause of the column blowing over and falling 

 away from the tree trunk. The rotted areas seemed also to extend 

 from one sheath inward to the next, gradually lessening in extent as 

 the middle was approached. The central tissues themselves were not 

 in the least discolored or rotted. In general, the rotted areas closely 

 resembled bud-rot tissues of the coconut, and the same kind of insects 

 that are found in diseased coconut trees, e. g., earwigs, were a})undant. 

 The odor from the rotting tissues, while bad, was not exactly tliat of 

 bud-rot. The whole aspect of these waiting sheaths was that of fleshy 

 tissue that had been completely cut off from the source of life and was 

 undergoing a normal course of decay. In the coconut palm affected 

 with bud-rot the undiseased tissues are white and the cells are turgid. 

 In the royal palm the unaffected unrotted tissues were white, but the 

 cells were rather flaccid. Because of the resemblance between this 

 disease of the royal palm and the bud-rot some of the tissues were 

 brought to Washington and attempts were made to plate out Bacillus 

 coll. All but one of the 23 plates made show^ed some signs of this 

 organism; the average was about 15 out of 100 colonies, in some plates 

 tlie proportion of Bacillus coli being higher and in others lower. The 

 other organisms were of a very great variety. That Bacillus coli was 

 present was demonstrated by transferring the suspected colonies, 

 which had reddened Dolt's medium, (1) to litmus milk, (2) to nitrate 

 bouillon, (3) to fermentation tubes containing dextrose, peptone, and 

 neutral red, and (4) to gelatin. The various cultures responded to 

 the tests as follows: 



In litmus milk 22 out of 31 gave typical reactions. 



In nitrate bouillon 31 out of 31 gave typical reactions. 



In neutral red fermentation tubes 26 out of 31 gave typical reactions. 



In gelatin 31 out of 31 gave typical reactions. 



Thus, over two-thirds of the tubes gave the customary reactions for 

 Bacillus coli. There can be very little question of contamination, 

 for the utmost care was taken to wash and soak large pieces of the dis- 

 eased material in mercuric chlorid, and then by means of sterile 

 knives portions from the interior of the pieces were removed to the 

 test tubes for plating out. There can be very little question that 

 Bacillus coli was in the diseased tissue. It may well be questioned, 

 however, whether this organism was the cause of the disease. Cer- 

 tainl}^ the mere fact of finding a small quantity of these germs in the 

 well-rotted tissues is no proof. Thus, the evidence in regard to this 

 royal-palm trouble being bud-rot is of doubtful value. It should be 

 noted in passing that along the coast near Maravi, 7 miles west of Bara- 

 coa, scattered at intervals, about 50 dead or dying royal palms may 

 be seen among many hundreds of health}^ ones. It should further be 



228 



