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with the following result : The oat- plant, grown in 

 the soil containing all the necessary substances 

 except Silica, was weak, and incapable of supporting 

 itself, thus proving what has been said of Silica 

 that it forms, in combination with lime, the bones 

 of the vegetable kingdom. In the soil containing 

 no Lime, the plant died just when producing the 

 second leaf ; the absence of Magnesia in another 

 case had the same effect as the absence of Silica 

 the plant could not support itself ; and in the soil that 

 was without either Sulphuric or Phosphoric Acid, 

 the plant, though but slightly weak, and otherwise 

 normal and upright, formed no seed whatever. 



These experiments prove that the absence of but 

 one of these substances affects the whole organism 

 of the pknt, and prevents the development of 

 certain organs. Thus we can understand why 

 some plants in an -apparently good soil do not arrive 

 at perfection, as the cause may sometimes be solely 

 due to the insufficiency or entire absence of a single 

 mineral. The non-production of seed in the 

 absence of Phosphoric Acid demonstrates the great 

 importance of this substance, and its absolute 

 necessity for all our grain crops. 



As different species of plants contain these 

 inorganic substances in various proportions, they 

 are distinguished according to the preponderating 

 constituent of the ashes as Potash plants, under 

 which designation we class beetroot, turnips. 



