OBJECT OF AGRICULTURE. 145 



peculiar influence on the development of particular 

 families. These substances either are already con- 

 tained in the soil, or are supplied to it in the form 

 of the matters known under the general name of 

 manure. But what does the soil contain, and what 

 are the components of the substances used as ma- 

 nure ? Until these points are satisfactorily deter- 

 mined, a rational system of agriculture cannot exist. 

 The power and knowledge of the physiologist, of the 

 agriculturist and chemist, must be united for the 

 complete solution of these questions ; and in order 

 to attain this end, a commencement must be made. 



The general object of agriculture is to produce in 

 the most advantageous manner certain qualities, or 

 a maximum size, in certain parts or organs of par- 

 ticular plants. Now, this object can be attained 

 only by the application of those substances which 

 we know to be indispensable to the development of 

 these parts or organs, or by supplying the conditions 

 necessary to the production of the qualities desired. 



The rules of a rational system of agriculture should 

 enable us, therefore, to give to each plant that 

 which it requires for the attainment of the object in 

 view. 



The special object of agriculture is to obtain an 

 abnormal development and production of certain 

 parts of plants, or of certain vegetable matters^ 

 which are employed as food for man and animals, or 

 for the purpose of industry. 



The means employed for effecting these two pur* 

 poses are very different. Thus the mode of culturCj 

 employed for the purpose of procuring fine pliable 

 straw for Florentine hats, is the very opposite to 

 that which must be adopted in order to produce a 

 maximum of corn from the same plant. Peculiar 

 methods must be used for the production of nitrogen 

 in the seeds, others for giving strength and solidity 

 to the straw, and others again must be followed 

 when we wish to give such strength and solidity to 

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