PART II. 
LECTURE VII. 
Importance of observing external objects . — Vegetables consist 
of two sets of organs . — Of the root — The Stem. 
The exercises which constitute the principal part of our pre- 
vious course of lectures, are chiefly designed to assist you in 
practical botany. It is not expected that you are to be the pas- 
sive receivers of instruction, but are to compare with real objects, 
the descriptions, with which you 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 deri- 
ved from external objects. Suppose an infant to exist who 
could neither hear, see, taste, smell, nor feel ; all the embryos 
of thought and emotion might exist within it ; it might have 
a soul capable of as high attainments 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 odors 
of flowers, the sensations of various flavors, which are derived 
from our sense of taste, the ideas of soft, smooth, or hard ; all 
these sensations must forever remain unknown to the soul con- 
fined to a body, unblest with the means of communication with 
the world around it : such a soul might be compared to the em- 
bryo of a plant, which, enclosed within the prison of a seed, 
would forever remain inert, were no means provided for its es- 
cape from this confinement, and no communication opened be- 
tween it and the air, the light, and the vivifying influence of the 
earth. 
Since our first ideas are derived from external objects, is it 
Study of external objects strengthens the mind — Abstract studies facilita- 
ted by acquaintance with the natural sciences — our first ideas derived 
from external objects — 
