THE SCHOOL OF ECONOMIC PLANTS. 1 79 



coriander, etc. ; and lastly, those which are eaten 

 in salad, as lettuce, succory, etc. Of the vege- 

 tables used in the arts, those which furnish tis- 

 sues, as flax and hemp, are distinguished from 

 those which afford die-stuffs, as madder and 

 woad. Those which serve for the nourishment 

 of animals are divided into grasses, leguminous 

 plants, and pasture herbs. A separate section 

 comprises vegetables of a peculiar nature, as the 

 tobacco, hop, teazle, etc. 



In a botanical garden the plants must be de- 

 tached for the convenience of studying them, but 

 for the object under contemplation they should 

 be disposed, as they are cultivated in fields or 

 gardens, in masses; which should be of four times 

 or at least twice the extent we have allowed 

 them, where the space will permit. 



To avoid putting the same plant into the same 

 ground, the series is begun every two years 

 at opposite extremities of the garden ; which 

 preserves the order, and changes the place of each 

 species. It is necessary also at intervals to renew 

 the seed, as the varieties degenerate when long 

 cultivated in the same spot, and often fecundate 

 each other, thus producing mixt species that re- 

 place the primitive type. 



Twenty thousand packets of seeds from this 

 garden are annually distributed to cultivators, 



12, 



