310 SYSTEM OF JUSSIEU. 



here and there more defined, this, or any other system, 

 becomes artificial, and liable to the more exceptions. 

 The way therefore to use this valuable work, so as to 

 ascertain an unknown plant, is, after turning to the 

 Order or Genus to which we conceive it most probably 

 allied, to read and study the characters and observa- 

 tions there brought together, as well as all to which 

 they may allude. We shall find we learn more from 

 the doubts and queries of Jussieu than from the asser- 

 tions of most other writers. We shall readily perceive 

 whether our plant be known to him or not ; and if at 

 the same time we refer it, by its artificial characters, to 

 the Linnaean System, we can hardly fail to ascertain, 

 even under the most difficult circumstances, whether it 

 be described by either of these authors. A student 

 may acquire a competent knowledge of natural orders, 

 with very great pleasure to himself, by repeatedly turn- 

 ing over the w^ork of Jussieu with any known plants in 

 his hand, and contemplating their essential generic 

 characters in the first place, and then what regards 

 their habit and affinities ; proceedint; afterwards to 

 combine in his own mind their several points of agree- 

 ment, till he is competent to form an idea of those 

 assemblages which constitute natural Classes and Or- 

 ders. This wall gradually extend his ideas ; w^hereas 

 a contrary mode would only contract them, and his 

 Jussieu would prove merely an artificial guide, without 

 the advantages of facility or perspicuity. 



