26 i EAMBLES OF A NATUEALIST. [Ch. XVI. 



principle be traceable in its promiscuous attacks. Upon a 

 close examination of the diseased parts, it is found that the 

 formative layer inside the bark dries up and turns black ; the 

 leaves then wither and fall off; and soon the bark is found 

 to be full of small perforations ; but no iusect of any kind 

 has ever been discovered in connection with the change, nor 

 has any fungus been charged with the destniction. Its 

 nature has been a mystery and a puzzle with the planters, 

 who have, for the most part in vain, sought for a cause, 

 either near or remote, and whose efforts to arrest it have 

 proved entirely unavaUiag. I have heard various suggestions 

 offered, some of them of the wildest character, to account 

 for the disease. That which Mr. Jose d'Almeida proposes 

 is by far the most reasonable, and in fact commends itself 

 to the judgment of the vegetable physiologist. It is that 

 the trees had long been unnaturally forced, by digging 

 trenches too closely around their spongioles, and by too 

 rich and long-continued manuring, by which heavy crops, 

 it is true, were for a time obtained, but which at last ex- 

 hausted the tree, so that the premature decay, thus brought 

 on by inflexible physiological laws, was incapable of being 

 arrested by any after-treatment. 



In conversation with a gentleman who once cultivated 

 nutpiegs on a large scale, I was assured by bini that he 

 could distinguish at least two forms of disease. In one of 

 these it was deep-seated and radical. In many trees which 

 he cut down for the purpose, he found that the central part 

 of the main stem was turning black ; and this gave the first 

 indications of the onset of the disease, which was soon 

 followed by the falling off of the leaves and the whitening of 

 the branches. 



With regard to the other form of disease, he distinctly 



