viir ROTATION OF CROPS 65 



mushrooms. It is generally noticed that plants cultivated 

 on the same land for many succeeding years are prone to be 

 injured by vegetable blights and insect pests. In nature, a Danger of 

 diversity of plants is found on the same soil ; and, when wkh^hTifws 

 natural laws are much interfered with, there is the proba- °^ nature, 

 bility of disastrous consequences ensuing. 



