AND FARMING PRODUCE. 313 



worn out, and was becoming extinct, from long 

 cultivation. When did a plant wear out with 

 cultivation ? Varieties may fail because nature 

 has not provided means for their renovation ; but 

 not so the species. Civilisation may as soon 

 extinguish man, as cultivation destroy the plant 

 it intends to cherish. Both may and will exhaust 

 what has become weak and effete, but they more 

 than compensate for the loss in the vigour and 

 variety they supply. There never existed a bane 

 without an antidote ; just as there never was action 

 without a counter action — never force in exercise 

 without its antagonist. And, as surely as there 

 is a check for smut and ergot in our grain crops, 

 so surely is there one for the blight and the 

 murrain among potatoes — when the causes of the 

 diseases have been truly discovered, and the condi- 

 tions which favour their spread most ascertained. 



As there are strong reasons for considering the 

 maladies just mentioned to be owing to a want 

 of due maturation, it may not be a digression, 

 too wide from our subject, briefly to examine them 

 physiologically at present. The blight which was 

 so rife during the last summer manifests itself 

 first in the fluid contained within the cellular 

 tissue of the two disks of the leaves, or in what 



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