THEORY OF VEGETATION. 33 



To these causes, assigned by British writers, may 

 be added the increase at population common to every 

 nation of Europe, and which, in Great Britain, is be- 

 yond all proportion greater than the progress of 

 agriculture ; the augmentation of cattle, which occa- 

 sions that of pasturage, and the diminution of til- 

 lage ;* the establishment of great farms at the ex- 

 pense of small ones, and the multiplication of parks 

 and pleasure grounds ; and, lastly, attractions of great 

 cities, and the continual draughts made upon the agri- 

 cultural population for the army and navy, and for 

 commerce and manufactures.! 



CHAPTER III. 



THEORY OF VEGETATION. 



VEGETABLES may be regarded as the intermediate 

 Jink in the great chain of creation between animals 

 and minerals. The latter grow by mere chymical 

 affinity, and by additions, sometimes analogous to 

 and sometimes foreign from their own nature ; 

 while plants, like animals, have an organization that 



* Mr. Hume quotes with approbation an author who com- 

 plains of the decay of tillage in the reign of Elizabeth, and who 

 ascribes it to the increase of pasturage, in consequence of the 

 restraints imposed on the exportation of grain, while that of 

 butter, cheese, &c., was free. The history of Europe, if read 

 with an eye to public economy, furnishes abundant proof that 

 the greatest obstructions to agriculture have arisen from the in- 

 terference of government. 



t Our author's account of the agriculture of England evi- 

 dently relates to the state of things in that country some fifty 

 years ago ; and, with this understanding, it is interesting as 

 showing more strikingly the extent of the improvements of every 

 kind which have been made since. 



