Proceedings of the Socitty. xxtii. 



a prospect well calculated to remove tbe fears sf the planter and 

 to leave do doubt in bis mind on the subject. 



» Tne writings of Hales, says Liebig in his Researches on the 

 1 Motions of Juices in Animals, bring to our century from a pre- 



> ceding one, the consoling certainty, and this is especially im- 

 » portant, that tbe cause of this decay is not to be looked for in 



* a degeneration of the plant, but depends on tbe combination 

 1 of certain conditions accidentally coincident ; and that these, 

 » when they are well ascertained and kept in view, enable tbe 



> agriculturist, if not to annihilate, at least to diminish, ibeir 



> hurtful influence. > 



> It was also a subject of wonder on examining the diseased 

 canes, and even those which afforded no trace of disorganisation, 

 to see tbe considerable quantity of insects, visible to the naked 

 eye, with which they were covered. By using magnifying glas- 

 ses, this world saemed to increase ad infinitum, and myriads of 

 animaiculse were perceived either at the sap-supplying bottom 

 of the leaf, or again on the periphery of the knot, in the articu- 

 lations, and even in tbe depth of tbe parenchyma ; and the 

 stems of some canes were found as deeply perforated as the 

 keentst metallic point could have done. 



» There were too, perceptible on several leaves, large brown 

 or rust-coloured spots which are known to be other plants living 

 at tbe expense of tbe vegetable on which they grow. 



> INow the difficulty here to be resolved was, to ascertain 

 whether these animals and parasitical plants accumulated in 

 compact masses on the cane, were not a consequence of the 

 disorganisation of the plant, and the hideous and ordinary 

 attendants of every animated body threatened with destiruction, 

 and if, lastly, what might be considered as the cause of the evil 

 was not, on the contrary, its effect. 



< The Fungi which have been observed on the potato plants. 



> says Liebig, and tbe putrefaction of the tubers, are not the 



> signs of a disease, but the consequence of the death of the 



* plant. » 



