238 K. <T. BUTLER. 



when the central slioot, formed of tlie innermost, partly expanded 

 leaves, withers and dies. In the vast majority of cases this indicates 

 that the lieart of the leaf-bud has been reached and the apical point, 

 which is the single locality in palms at which new leaves are formed, 

 has been killed. Except in rare cases, to be described below, 

 withering of the central shoot is a fatal symptom in palms ; no new 

 leaves are produced ; the older ones gradually dry up ; no new food 

 is manufactured, and tho\igh the tree lives for a time on food- 

 reserves stored in the older tissues, these become eventually exhaust- 

 ed and total death ensues. A second period which may be taken 

 as indicating "death" is when every leaf has withered and fallen 

 and nothing is left but a bare pole. Long before this has happened 

 all chance of recovery has disappeared, and it is therefore more 

 satisfactory to select the first-mentioned indication in calculating 

 the duration of the disease. 



An experiment to determine this was carried out in 1908. 

 Three rather young palms were inoculated on one of the outer 

 leaf-sheaths, that selected being, as usual in the inoculations, 

 not the outermost liard, dry sheath, but the clean moist 

 one just below. They were kept under observation and after a 

 little over five months the central shoot in two was found to be 

 withering. The third still showed no external symptom and, as 

 observations ceased soon after, its subsequent fate is not known. 

 The other two were cut down and examined. One had 25 fully 

 formed leaf-sheaths inside that inoculated, the other 30. In the 

 first the infection, starting from the point inoculated, had penetrat- 

 ed twelve sheaths in immediate contact one beneath another. After 

 the 12th sheath there appeared to be several quite free from infec- 

 tion spots. Then those in the centre of the crown, and the base of 

 the central shoot itself, were severely attacked, the latter being 

 reduced to a putrid mass Passing through several of the disease 

 spots on the outer sheaths were the tunnels of the rhinoceros beetle, 

 and these were continued on through some of the unmarked sheaths 

 to the base of the central shoot. Either the parasite was carried 

 in by the beetle, or the course taken by it from the 12th sheath 



