1 INTRODUCTION. 



advanced until tins preliminary difficulty is overcome. Those who hold 

 a language of this kind must be so unacquainted with the subject, that their 

 arguments, if they can be called by such a name, scarcely deserve a reply. 

 The objection has, however, been made, and must be answered. 



In natural history many facts have been originally discovered by minute 

 and painful research, which, when once ascertained, are readily to be 

 detected by some more simple process, of which Botany is perhaps the 

 most striking proof that can be adduced. The first question to be deter- 

 mined by a student of Botany, who wishes to inform himself of the name, 

 affinities, und uses of a plant, appears to be, whether his subject contains 

 spiral vessels or not, because the two great divisions of the vegetable king- 

 dom, called Vasculares and Cellulares, are characterized by the presence 

 or absence of these minute organs. It is true, we have learned by careful 

 observation, and multiplied microscopical analyses, that vascular plants have 

 spiral vessels, and cellular plants have none ; but it is not true, that in prac- 

 tice so minute and difficult an inquiry needs to be instituted, because it has 

 also been ascertained that all plants that bear flowers have spiral vessels, 

 and are therefore Vascular ; and that vegetables which have no 

 flowers are destitute of spiral vessels, and are therefore Cellular ; so that 

 the inquiry of the student, instead of being directed in the first instance to 

 an obscure but highly curious microscopical fact, is at once arrested by the 

 two most obvious peculiarities of the vegetable kingdom. 



Among vascular plants two great divisions have been formed; the 

 names of which, Monocotyledons and Dicotyledons, are derived from the 

 former having usually but one lobe to the seed, and the latter two, — a 

 structure much more difficult to ascertain than the presence or absence of 

 spiral vessels, and more subject to exceptions. But no botanist would 

 proceed to dissect the seed of a plant for the purpose of determining to 

 which of these divisions it belonged, except in some special cases. We 

 know that the minute organization of the seed corresponds with a peculiar 

 structure, stem, leaves, and flowers, the most, highly developed, and most 

 easily examined parts of vegetation ; a botanist, therefore, prefers to exa- 

 amine the stem, or the leaf of a plant, to see whether it is a Monocotyledon 

 or a Dicotyledon, and does not find it necessary to anatomize the seed. 



The presence or absence of albumen, the structure of the embryo, the 

 position of the seeds or ovula, the nature of the fruit, the modifications of 

 the flower, will, I presume, be hardly brought forward as other difficult 

 points for the student of the Natural System, because, whether the one 

 system or the other be employed, he must make himself acquainted with 

 such facts, for the purpose of determining genera. The common Toad- 

 flax cannot be discovered by its characters in any book of botany, without 

 the greater part of this kind of inquiry being gone through. 



In the determination of genera, however, facility is entirely on the side 

 of the Natural System. Jussieu has well remarked, " that whatever trouble 

 is experienced in remembering or applying the characters of natural 

 orders, is more than compensated for by the facility of determining genera, 

 the characters of which are simple in proportion as those of orders are 

 complicated. The reverse takes place in arbitrary arrangements, where 

 the distinctions of classes and sections are extremely simple and easy to 

 remember, while those of genera are in proportion numerous and com- 

 plicated." 



Let me not, however, be misunderstood in what I have been saying of 

 the supposed difficulties of the Natural System. Far bo it from me to 



