BLACK BLIGHT IN WHEAT. 159 



" Land may be too rich for corn crops ; and it is 

 " better to keep it in a well-balanced condition, 

 " or in a medium state of productiveness, than 

 " in too fertile a state. The greater quantity of 

 " sap and juices in vegetables, growing on highly 

 " cultivated lands, it is evident, must necessarily 

 " render them more susceptible of the effects of 

 " sudden and extreme changes, and, conse- 

 " quently, more liable to disease. Besides, as 

 " mushrooms are produced on beds of dung, 

 " great quantities of manure must promote the 

 " growth of fungi, or parasitical plants, on the 

 " crops of wheat, if they are once infected. The 

 " wheat produced on the site of a dunghill is 

 " always rusted, even in the most favourable 

 " seasons ; and if the whole field is a species of 

 " dunghill, how can it escape ?" 



" A too frequent repetition of crops of wheat, 

 " more especially when accompanied by great 

 " quantities of manure to force a crop, will often 

 " have the same effect. The rust was but little 

 " known in the western or the northern parts of 

 " England, or the southern counties of Scotland, 

 " until of late years, when every exertion has 

 " been made to increase the quantity of that 

 " grain." 



Sir John Sinclair also says, "Among the reme- 

 " dies likely to diminish the effects of this fatal 



