THE ART OF CULTURE. 



49 



fertile, the only difference which can be ob- 

 served being in its height and size, in the 

 number of its twigs, branches, leaves, blos- 

 soms, and fruit. Whilst the individual or- 

 gans of a plant increase on a fertile soil, 

 they diminish on another where those sub- 

 stances which are necessary for their forma- 

 tion are not so bountifully supplied ; and 

 the proportion of the constituents which 

 contain nitrogen and of those which do not 

 in plants varies with the amount of nitro- 

 genous matters in their food. 



The developement of the stem, leaves, 

 blossoms, and fruit of plants is dependent on 

 certain conditions, the knowledge of which 

 enables us to exercise some influence on 

 their internal constituents as well as on their 

 size. It is the duty of the natural philoso- 

 pher to discover what these conditions are ; 

 for the fundamental principles of agriculture 

 must be based on a knowledge of them. 

 There is no profession which can be com- 

 pared in importance with that of agricul- 

 ture, for to it belongs the production of food 

 for man and animals ; on it depends the 

 welfare and developement of the whole 

 human species, the riches of states, and all 

 commerce. There is no other profession in 

 which the application of correct principles 

 is productive of more beneficial effects, or is 

 of greater and more decided influence. 

 Hence it appears quite unaccountable, that 

 we may vainly search for one leading prin- 

 ciple in the writings of agriculturists and 

 vegetable physiologists. 



The methods employed in the cultivation 

 of land are different in every country, and 

 in every district ; and when we inquire the 

 causes of these differences, we receive the 

 answer, that they depend upon circum- 

 stances. (Les circonstances font les assole 

 ments.) No answer could show ignorance 

 more plainly, since no one has ever yet de- 

 voted himself to ascertain what these cir- 

 cumstances are. Thus also when we inquire 

 in what manner manure acts, we are an- 

 swered by the most intelligent men, that its 

 action is covered by the veil of Isis j and 

 when we demand further what this means, 

 we discover merely that the excrements of 

 men and animals are supposed to contain 

 an incomprehensible something which assists 

 in the nutrition of plants, and increases their 

 size. This opinion is embraced without 

 even an attempt being made to discover the 

 component parts of manure, or to become 

 acquainted with its nature. 



In addition to the general conditions, such 

 as heat, light, moisture, and the component 

 parts of the atmosphere, which are neces- 

 sary for the growth of all plants, certain 

 substances are found to exercise a peculiar 

 influence on the developement of particular 

 families. These substances either are al- 

 ready contained 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 com- 

 ponents of tne substances used as .manure? | 

 7 



Until these points are satisfactorily deter- 

 mined, a rational system of agriculture can- 

 not 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 particular plants 

 Now, this object can be attained only by the 

 application of those substances which we 

 know to be indispensable to the developement 

 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 agricul- 

 ture should enable us, therefore, to give to 

 each plant that which it requires for the at- 

 tainment of the object in view. 



The special object of agriculture is to ob- 

 tain an abnormal developement and produc- 

 tion of certain parts of plants, or of certain 

 vegetable matters, which are employed as 

 food for man and animals, or for the pur- 

 pose of industry. 



The means employed for effecting these 

 two purposes are very different. Thus the 

 mode of culture, employed for the purpose 

 of procuring fine pliable straw for Floren- 

 tine hats, is the very opposite to that which 

 must be adopted in order to produce a maxi- 

 mum of corn from the same plant. Peculiai 

 methods must be used for the production oi 

 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 the straw 

 as will enable it to bear the weight of the 

 ears. 



We must proceed in the culture of plants 

 in precisely the same manner as we do in 

 the fattening of animals. The flesh of the 

 stag and roe, or of wild animals in general, 

 is quite devoid of fat, like the muscular flesh 

 of the Arab ; or it contains only small quan- 

 tities of it. The production of flesh and fat 

 may be artificially increased; all domestic 

 animals, for example, contain much fat. 

 We give food to animals, which increases 

 the activity of certain organs, and is itself 

 capable of being transformed into fat. We 

 add to the quantity of food, or we lessen the 

 processes of respiration and perspiration by 

 preventing motion. The conditions neces- 

 sary to effect this purpose in birds are dif- 

 ferent from those in quadrupeds ; and it is 

 well known that charcoal powder producer* 

 such an excessive growth of the liver of a 

 goose, as at length causes the death of the 

 animal. 



The increase or diminution of the vital 

 activity of vegetables depends only on heat 

 and solar light, which we have not arbitra- 

 rily at our disposal : all that we can do is to 

 supply those substances which are adapted 

 for assimilation by the power already pre- 

 sent in the organs of the plant. But wha 



