VEGETABLE EXTRACT. 



growth, and tenacious of life, such as many of the Moss 

 es, and some of the succulent plants, do indeed effect 

 the dev elopement of their parts, without the aid of 

 any other nourishment beyond what they derive from 

 the atmosphere. But plants of rapid growth, such as 

 annuals, can never effect that developement, without 

 the aid of nourishment derived from the soil. Saus- 

 sure tried the experiment upon Beans, Peas, and cress- 

 es, by placing them in pure sand, and moistening them 

 with distilled water. They grew indeed, and some of 

 thern even flowered, but never produced perfect seeds. 

 It is plain, therefore, that some essential principle of 

 nourishment was wan'ing, which is furnished by the 

 soil ; and that atmospheric air and water, are not the 

 only principles constituting the food of plants. 



3. VEGETABLE EXTRACT.— When it was found 

 that atmospheric air and water are not, even conjointly 

 capable of furnishing the whole of the aliment necessary 

 to the developement of the plant, it was then alledged 

 that, with the exception of water, all substances con- 

 stituting a vegetable food must at least be administered 

 to the plant in a gaseous state. But this also is a con- 

 jecture unsupported by proof; for even with regard to 

 such plants as grow upon the barren rock, or in pure 

 sand, it cannot be said that they receive no nourishment 

 whatever besides water, except in a gaseous state. 

 Many of the particles of decayed animal and vegetable 

 substances, which float in the atmosphere and attach 

 themselves to the leaves, must be suffered to enter the 

 plant in solution with the moisture which the leaves im- 

 bibe ; and so also similar substances contained in the 

 soil must be supposed to enter it by the root ; but 

 these substances may certainly contain vegetable nour- 

 ishment ; and they will perhaps be found to be taken 



