126 HISTORY AND CAUSE OF THE COCONUT BUD-EOT. 



Sunlight. — Agar plates were made and half of each of them covered 

 with black paper; they were then set on ice in direct sunlight, the 

 ice serving to counteract the heat effect of the sun's rays. This 

 experiment was carried on in the middle of January, about 1 p.m., 

 with a somewhat hazy sun. The plates were thickly sown. Those 

 exposed for one hour failed to show any effect whatever from the 

 sunlight, and developed in an apparently normal manner. 



This experiment was repeated on February 2, at noon, in bright 

 sunlight, and salt was added to the ice to reduce to a minimum the 

 liability of the sun's heat affecting the organism. Exposures to the 

 du-ect sunlight were made for 30, 45, 75, 90, and 120 minutes. In 

 24 hours all the plates showed good growth on the unexposed half 

 of the dish. On the plate exposed for 30 minutes only about half 

 as many colonies appeared on the exposed side as on the unexposed. 

 On the plate exposed 45 minutes the reduction was still greater, but 

 the colonies could not be definitely counted on account of their ten- 

 dency to coalesce. On the plate exposed for 60 minutes about 

 one-eighth as many colonies appeared on the exposed as on the unex- 

 posed side. On the plate exposed 75 minutes no colony appeared 

 on the exposed side. The same condition was true for the plates of 

 90 and 120 minutes exposure. In 36 hours six submerged colonies 

 were visible on the 120-minute plate, and some were visible on aU 

 the others, in addition to the spread of the colonies from the unex- 

 posed side of the plate. 



INOCULATIONS FOR THE COMPARISON OF THE COCONUT ORGANISM 



AND BACILLUS COLI. 



In earlier pages of this paper it has been shown that a certain 

 organism could produce diseased conditions by artificial inoculations 

 into healthy coconut trees, identical with typical bud-rot. On 

 subsequent pages it has been shown that this coconut organism is 

 practically identical in its cultural features with the common Bacillus 

 coli. The next step was to produce conditions similiar to bud-rot by 

 means of inoculations with Bacillus coli derived from animals. For 

 this purpose several experiments have been carried out in the green- 

 house Vvdth coconut seedlings. The coconut organism was inoculated 

 into some seedlings for comparison with the Bacillus coli inoculations. 



Experiment No. 1. 



Inoculations with the coconut organism and with Bacillus coli 

 (from animals) were made into coconut seedlings on February 17 

 from cultures of February 16. At the same time a solution of 

 ammonium oxalate was injected into a seedling. Xo check inocula- 

 tions other than this were made at this time, 



228 



