PULI' ACE. 
VI I 
System et ultimum in botanicis desideratum. He could not have 
expected that his artificial method should exist when the science had 
made sufficient progress to enable botanists to revert to the principles o 
natural arrangement, the temporary abandonment of which had been 
solely caused by the difficulty of defining its groups. This difficulty 
no longer exists ; means of defining natural assemblages, as certain as 
those employed for limiting artificial divisions, have been discovered by 
modern botanists ; and the time has arrived when the ingenious expe- 
dient of Linnaeus, which could only be justified by the state of Botany 
when he first entered upon his career, must be finally relinquished. » We 
now know a great deal of the phenomena of vegetable life ; by modern 
improvements in optics, our microscopes are capable of revealing to us 
the structure and the combinations of the minutest organs ; repeated 
observations have explained the laws under which the external forms 
of plants are modified ; and it is upon these considerations that the 
Natural System depends. 
In the first edition of this work I entered into some explanation of the 
fallacy of the common opinion that the artificial system of Linnaeus is 
easy, and the Natural System difficult of application. Within the last 
five or six years, however, the sentiments of the public have undergone 
so great a change upon this subject that I no longer find it necessary to 
go into such details. All, therefore, that I propose to do on this occa- 
sion is to offer a few very general remarks upon the Natural System 
itself. 
The principle upon which I understand the Natural System of Bo- 
tany to be founded is, that the affinities of plants may be determined 
by a consideration of all the points of resemblance between their various 
parts, properties, and qualities ; that thence an arrangement may be 
deduced in which those species will be placed next each other which 
have the greatest degree of relationship ; and that consequently the 
quality or structure of an imperfectly known plant may be determined 
by those of another which is well known. Hence arises its superiority 
over arbitrary or artificial systems, such as that of Linnaeus, in which 
there is no combination of ideas, but which are mere collections of iso., 
lated facts, not having any distinct relation to each other. 
This is the only intelligible meaning that can be attached to the term. 
Natural System, of which Nature herself, who creates species only, 
knows nothing. Our genera, orders, classes, and the like, are mere 
contrivances to facilitate the arrangement of our ideas with regard 
