Phenomenon manifested in the Sugar-Cane. 118. 



conclude, were exhaustion of soil the specific cause, that 

 such canes, on the contrary, should have been attacked the 

 first and most extensively. 



The general appearance of the fields exhibited partial 

 spot on the edges and in the interior of the squares where 

 the cane-leaves were marked longitudinally, with light 

 yellow lines and in such a manner as to give them a 

 ribbon-like appearance. This peculiarity was remarkable 

 sometimes at the extremity of the leaf, sometimes at the 

 base, though the leaf most frequently seemed scorched as 

 if it had been subjected to the action of an atmospheric 

 current which had violently traversed the squares of canes. 



I moreover remarked that the finest canes, those spring- 

 ing from a soil containing greater proportion of organic 

 matters, consequently rich in nitrogen, and particularly 

 those situated to the windward of the squares, were much 

 much severely attacked than the canes that grew in the 

 vicinity of the forests, and above all, in the lines most 

 approximative to the forest. 



Had the disease been produced by the immediate effect 

 of manures, the roots and the shoots would have been the 

 first attacked, and it would necessarily have developed itself 

 at the base of the cane where its further progress might 

 have been either hindered or altogether arrested; the 

 phenomenon however, was remarked rather on the upper 

 parts of the plant, at the end and towards the middle of 

 the leaves, whilst the body of the cane was perfectly un- 

 touched. It was every where observable when the top of 

 the cane had been destroyed, that the stem vigorously 

 pushed forth new and perfectly healthy shoots. 



The direction assumed by marks on the leaves of the 

 diseased plant, led me to attribute the phenomena of their 



