PART II. 
VEGETABLE PHYSIOLOGY. 
LECTUKE YI. 
tMPORTANCE OF OBSERVING EXTERNAL OBJECTS. ^VEGETABLES CON 
SIST OF TWO SETS OF ORGANS. OF THE ROOT. 
28. The exercises which, constitute the principal part of our 
previous course of lectures, are chiefly designed to assist the 
scriptions which are presented. By systematic attention to 
external objects the mind is disciplined, and prepared the 
better to pursue abstract studies, where the subjects of inves- 
tigation cannot, like the plants, be looked at and handled. 
a. 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 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 coloring ; the harmony of sounds, the fragrant 
odors of flowers, the various flavors, which are derived from our sense of taste, the 
ideas of soft, smooth, or hard ; all must forever remain unknown to the soul con- 
fined to a body having no means of communication with the world around it. The 
soul, in its relation to e:sternal objects, may be compared to the embryo plant, 
which, imprisoned' within the seed, would forever remain inert, were no means pro- 
vided for its escape from this confinement ; and no communication opened, between 
U, and the air, the hght, and vivifying influence of the earth. 
h. Since our first ideas are derived from external nature, is it not a rational con 
c''usion 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 os 
human sciences, overlook the works of God ? 
29. In plants, as well as animals, each part or organ is inti- 
mately connected with the whole ; and the vegetable, as weli 
as the animal being, depends for its existence on certain laws 
of organization. Vegetable organs may be considered under 
two classes : 1st, including such organs as jpromote the growth 
of the plant, as the root, leaves, &c., called organs of vegeta- 
tion / 2d, such as perfect the seed^ and thus provide for the re- 
production of the species, called organs of fructification. 
28. Stndy of external objects strengthens the mind — Abstract studies facilitated by acquaintance 
<vith the natural sciences. — a. Our first ideas gained by the senses — Analogy between the soul and the 
embryo plant. — b. We should not confine our attention exclusively to books.— 29. Vegetable, as well as 
inimal existence, depends on certain laws of organization — Two kinds of organs of vegetables. 
