Diseases 233 



leaves were removed, one by one, from this 

 standing tree, and the disease could be plainly 

 seen at the leaf-bases, and at the bases of the 

 spikes which were losing their nuts. In this 

 case the disease had not yet reached the central 

 leaves, but observe that in many cases in which 

 I found the rot to be in the centre, this condition 

 was nearly always preceded by a gradual shed- 

 ding of the nuts, and the progress of the disease 

 at the base of the leaves. Moreover, in the 

 case of some trees which had healthy central 

 leaves, but whose nuts were gradually falling, 

 I have removed all the lower leaves and spikes 

 up to as high as the lowest healthy-appearing 

 sword, thus leaving three or four green swords, 

 and six or seven upright only half-opened green 

 leaves. I pruned the trees in this way and left 

 just an advancing margin of the rot. This 

 infected the healthy sword, and in the course 

 of a few days it split and a discoloured, wilted 

 flower-spike emerged instead of a healthy white 

 one. I left this diseased flower-spike with the 

 diseased tissues for a week or so, and then 

 removed the spike and subtending leaf, but did 

 not disinfect the adjacent tissues. By a slit into 

 the lowermost remaining sword it was seen to 

 be perfectly healthy. In the course of a week 

 it, too, had turned to a chocolate-brown. Thus, 

 if left, the disease would gradually spread from 

 the outside to the inner and softer tissues of 

 the heart, which succumb rapidly to the 

 disintegrating action." 



