184 Mr. Roscoe on Jrraugemenis of Plants. 



necessary to its support, but to elicit those peculiar qualities 

 of acids, salts, gums, resins and aroma, by which they are di- 

 stinguished, and on which their natural combinations so ulti- 

 mately depend. When these facts are sufficiently developed, 

 the system then proceeds to arrange the individuals of the ve- 

 getable kingdom, not by their exterior phaenomena, but by 

 those primitive and secret alliances by which nature has bound 

 them together; uniting such as are most nearly allied, and se- 

 parating such as have no inherent affinity to each other. In 

 an artificial system, some plain and obvious distinction, such 

 for instance as the number of the stamina, is decisive of the 

 character. In a natural system this must depend on some 

 more remote circumstance, such as the mode of germination 

 of the plant, and which, though deeply founded in nature, 

 cannot at the instant be demonstrated, but must for the pre- 

 sent be admitted on the credit of the founder. Even to de- 

 termine the primary distinctions on which such a system should 

 rest, is a matter of no small difficulty: and notwithstanding 

 the concurrent authority of both Linnaeus and Jussieu, it is 

 by no means certain that the number of cotyledons with which 

 a plant germinates is the most secure foundation; or whether, 

 for instance, the classification by Gasrtner from the seeds them- 

 selves is not to be preferred. Hence there arises between the 

 two modes of arrangement this important distinction, that an 

 artificial method, devised and completed by one person, may 

 readily be communicated to another, and is as intelligible to 

 the student as to the preceptor; whilst, on the contrary, the 

 knowledge of a natural system is chiefly confined to the author, 

 and cannot be fully attained by any other person without en- 

 tering into the same investigations, and ascertaining the same 

 facts; many of which might perhaps afford different results, 

 or lead to different conclusions. Whenever a pretended na- 

 tural system relinquishes these primary distinctions, and at- 

 tempts to arrange the genera and species of plants by their 

 exterior phaenomena, it is no longer natural but artificial ; and 

 the superstructure being wholly different from the basis, it 

 becomes incongruous and absurd; neither furnishing the re- 

 condite information which is obtained from the study oiP the 

 natural relations of plants, nor affording us those advantages 

 of a ready discrimination which we derive from an artificial 

 arrangement. As long as these truths are acknowledged and 

 acted upon, a real progress will be made in the science ; and 

 to no country has the world been of late moi'e indebted than 

 to France, for that knowledge and information which a deep 

 inquiry into the recesses of the vegetable kingdom can alone 

 supply ; although this country may also boast of many distin- 

 guished 



