PART IL 
LECTURE VI 
IMPORTANCE OF OBSERVING EXTERNAL OBJECTS — VEGETABLES CONSIST OF TWO 
SETS OF ORGANS — OF THE ROOT. 
The exercises which constitute the principal part of our previous 
course of lectures, are chiefly designed to assist you in practical bot- 
any. It is not expected that you are to be the passive receivers of 
instruction, but that you are to compare with real objects, the de- 
scriptions which are presented ; by doing this faithfully, you will find 
your minds gradually strengthened, and more competent to compare 
and judge in abstract studies, where the subjects of investigation are 
in the mind only, and cannot, like the plants, be looked at with the 
eyes, and handled with the hands. 
All our thoughts, by means of the senses, are originally derived 
from external objects. Suppose an infant to exist, who could neither 
hear, see, taste, smell, nor feel ; all the embryos of thought and emo- 
tion might exist within it; it might have a soul capable of as high at- 
tainments as are within the reach of any created beings ; but this 
soul, while thus imprisoned, could gather no ideas ; the beauty of 
reflected light, constituting all the variety of colouring ; the harmony 
of sounds, the fragrant odours of flowers, the various flavours, which 
are derived from our sense of taste, the ideas of soft, smooth, or 
hard ; all must for ever remain unknown to the soul confined to a 
body having no means of communication with the world around it. 
The soul, in its relation to external objects, may be compared to the 
embryo plant, which, imprisoned within the seed, would for ever re- 
main inert, were no means provided for its escape from this confine- 
ment, and no communication opened between it and the air, the light, 
and vivifying influence of the earth. 
Since our first ideas are derived from external nature, is it not a 
rational conclusion that we should add to this original stock of 
knowledge, by a continued observation of objects addressed to our 
senses ? After the years of infancy are past, and we begin to study 
hooks, should we, neglecting sensible objects, seek only to gain ideas 
from the learned ; or, in other words, should we, in the pursuit of 
human sciences^ overlook the works of God ? 
Having now enabled you to understand the method of analyzing 
plants, we shall proceed to consider more fully the difierent organs 
of plants, with the uses of each, in the vegetable economy. 
In plants, as well as animals, each part or organ is intimately con- 
nected with the whole ; and the vegetable, as well as the animal be- 
ing, depends for its existence on certain laws of organization. 
We shall consider the vegetable organs under two classes ; the 
first, including such organs as promote the growth of the plant, as the 
root, leaves, &c. ; the second, such as perfect the seed, and thus pro- 
vide for the reproduction of the species, called organs of fructifica- 
tion. 
Study of external objects strengthens the mind— Abstract studies facilitated by ac- 
quaintance with the natural sciences — Our first ideas gained by the senses — Analogy 
between the soul and the embryo plant— VVe should not confine our attention exclu- 
sively to books — Vegetable, as well as animal existence, depends on certain laws of 
organization— Two kinds of organs of vegetables. 
