52 HISTOBY AND CAUSE OF THE COCONUT BUD-EOT. 



ism. From these colonies transfers were made to litmus milk, which 

 in every case reddened the litmus and coagulated the milk and 

 subsequently became partially bleached as in the true coconut organ- 

 ism. Transfers were made from these litmus-milk tubes to fer- 

 mentation tubes containing peptone, dextrose, and neutral red, and 

 in every case the typical greenish-yellow reaction took place in the 

 closed arm of the tubes and gas was produced, usually the ordinary 

 amount, though in one series of tubes it ran as high as 70 to 90 per 

 cent. Transfers were also made from the litmus milk to nitrate 

 bouillon, and tests after 48 hours' growth at 32° C. showed a reduc- 

 tion of the nitrate in every case. Similarly, transfers from the nitrate 

 bouillon to beef gelatin + 15 kept in the thermostat at 37° C. for 

 48 hours and afterwards placed in an ice box to harden, failed to 

 show any liquefaction of the gelatin. Cultures of these organisms 

 in Dunham's solution when tested for indol showed a good pink 

 reaction. 



Thus, in all these tests certain bacteria responded to the usual 

 tests for the coconut organism. The proportion of this organism 

 to the total amount found in the dejecta of the buzzard was, however, 

 small. 



In the tops of palms rats have frequently been found as well as 

 other animal life, but it does not appear likely that these serve as 

 carriers of the disease. An attempt was made to isolate the coconut 

 organism from excreta of rats, but without success. 



It will be seen in the following pages that the organism causing bud- 

 rot is Bacillus coli, or at least an organism indistinguishable from it. 

 This organism is one that has been known for a long time as being 

 of almost universal distribution and one that is commonly found in 

 the intestines of man and some of the lower animals. The wide- 

 spread distribution of Bacillus coli would seem to coincide with the 

 widespread occurrence of the bud-rot, for, as described on other 

 pages, a disease identical with this appears to occur in almost all 

 parts of the tropical world. If Bacillus coli is to be found in so 

 many countries and is the cause of bud-rot, how is it that there are 

 any regions free or apparently free from this disease? Tliis is a 

 question that naturally arises, and one that does not lend itself to 

 an easy solution. To illustrate this: Bacillus coli is shown to be the 

 cause of the coconut bud-rot in Cuba, but this disease does not 

 appear to occur in Porto Rico. Bacillus coli undoubtedly occurs in 

 Porto Rico but docs not cause the coconut disease. Why is it that 

 the organism that causes the disease in one locality does not cause 

 it in another when it is present ? A plausible explanation is in the 

 supposed absence of the particular carrier of the infection in these 



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