242 On an improved Mode of Cultivating the Melon. 



experiments to ascertain by what organs, and under what 

 circumstances, the lifeless inorganic matter, which is absorbed 

 by the roots of plants, becomes converted into their true 

 sap, or living vegetable blood; and the result of every expe- 

 riment has led me to believe, that in all cases where plants 

 possess leaves, as distinct organs, it is in such organs alone, 

 and under the influence of light, that this process takes 

 place. The powers, which roots of various forms and cut- 

 tings, and other detached parts of plants, possess of emitting 

 foliage have appeared to me to be wholly, in all cases, de- 

 pendent upon the presence of true sap previously deposited 

 within them. Like the cotyledon of seeds they appear to 

 be reservoirs only, which contain, but never create : and it 

 has been long ascertained that seedling plants perish, or at 

 best scarcely retain life, if deprived of their cotyledons, even 

 after the radicle has penetrated deeply into the soil, and the 

 elongated plumule has reached its surface ; a discovery 

 which appears to be universally given to Bonnet ; but which 

 belongs to Malpighi. 



The following experiment, with many others which I could 

 adduce, appears to prove that powers have been given to 

 the mature leaf, which have been denied to the roots and 

 branches of plants, and to the cotyledons of their seeds, un- 

 less the latter expand into, and assume, as they in many cases 

 do, the form and office of leaves. In an early part of the 

 summer some leaves of Mint, (Mentha piperita,) without 

 any portion of the substance of the stems, upon which they 

 had grown, were planted in small pots, and subjected to arti- 

 ficial heat, under glass. They emitted roots and lived more 

 than twelve months, having assumed nearly the character of 



