INTEODUCTION. S 



ture, it seems better strictly to confine our attention 

 to the action of the simplest vital forces ; for the gene- 

 ral nature of these has been undoubtedly ascertained, 

 and is easily understood by every class of readers. 

 It is certain, for instance, that plants breathe, digest, 

 and perspire ; but it may be a question whether the 

 exact nature of their respiration, digestion, and per- 

 spiration is beyond all further explanation : it is 

 therefore better to limit our consideration to the na- 

 ked fact, which is all that it imports the gardener to 

 know, without inquiring too curiously into those phe- 

 nomena. For it must always be remembered, that 

 the object of a work like the present is not to eluci- 

 date the laws of vegetable life in all their obscure 

 details, but to teach, to those acquainted with the art 

 of gardening, what the principles are upon which 

 their practice is founded. 



4. In order to attain this end, it is necessary, in the 

 first place, to explain briefly, but distinctly, the na- 

 ture of those vital actions which have a direct refer- 

 ence to cultivation ; omitting everything that tends 

 to embarrass the subject, or which is not susceptible 

 of a direct practical application ; and in the next 

 place, to show how those facts bear upon the routine 

 of practice of the horticulturist, by making them ex- 

 plain the reason of the treatment which is employed 

 in various branches of the gardener's art 



5. The first part of this work will therefore em- 

 brace the principal laws and facts in vegetable phy- 

 siology, as deduced from the investigations of the 

 botanist; and the second, the application of those 



