VEGETABLE PnYSIOLOGY. 
adoption of good methods, and by remembering the golden rule, not to try for too much. All I ask of 
the reader is, to read cai'efully and attentively, and to consider well the connexion of the diii'erent 
parts of the subject, as successively placed before him, since the various phenomena of life, iu vege- 
tables as in animals, are so closely connected with the laws of the dead world, as well as with each 
other, that no sound knowledge of vegetable physiology can be acquired without taking account at 
once of the physical and chemical principles which are continually active in modifying vegetation, 
and of the phj'siological principles wliich give to it its peculiar character in creation. 
I shall fh-st point out, as briefly as possible, the chief of these laws of the dead or inorganic world 
that must be mastered before we can comprehend the phenomena of life and growth ; and, in so doing, 
I shall endeavour to find illusti'ations in facts or operations, that every one may verify by observation 
in the cu-cumstances of daily life ; by this means, to impress them with a reality and distinctness, 
which mere statements would not possess. From these we vnl\ pass to an account of the constraction 
of plants — the nature and condition of the parts of which they are composed and built up ; going only 
so deep into the subject as is necessary for general practical purposes, passing over the delicate minu- 
tiae, and also over such portions of the subject as are still subjects of discussion, as foreign to our 
purpose. The chief modifications of form depending on this internal construction, will be the next 
pointed out ; and then we shall have anived at a condition in which the general nature of the pro- 
cesses exhibited in the life of plants, such as their growth, reproduction, &c., may be comprehended in 
then- full meaning. This portion wUl, of course, involve what is called the nutrition of plants ; and 
we shall, therefore, also have to examine their relation to the atmosphere, the soil, and similar external 
agencies. 
The phenomena of a special character, such as the colour, odour, &c., will be considered in theii' 
tui'U, and the body of knowledge thus accumulated, besides the dii'ect practical use to which it may 
be applied, will also, it is hoped, faciUtate the comprehension of the great pm-poses of the vegetable 
world, its place in the economy of natm'e ; and, lilvc all true knowledge, lead to a better, because a more 
enUghtened, aclaiowledgment of the goodness and power of its beneficent Creator. 
At the same time, however, I would wish to add, that, although I have insisted strongly on 
the necessity of dii-ecting attention chiefly to deflnite laws and facts, I do not wish it to be imagined 
that I intend to give a diy, pm-ely logical, accomit of the subject. I shall seize every opportunity to 
enhven the papers with such illustrations from general subjects as will help to explain my meaning 
more clearly, and, — wliile keeping distinctly in view one main tlu'ead of argiunent through the whole 
series, — -svill turn aside, as occasion may arise, to point out, episodically, interesting or amusing facts, 
wherever opportunity ofiers of so doing. And, indeed, it is impossible to cast oiu- eyes anywhere into 
the economy of nature, — whether in the grand manifestations of power uttered in the phenomena of 
geology, or even in those of meteorology, as going on ai'omid us now, or in the marvellously delicate 
operations which we can only discern by means of our microscopes, — without finding an inexhaustible 
source of interesting reflection ; every new fact we meet with, seems to open out a new prospect beyond 
it of things undreamt of before ; every new law we determine, exhibits to us more clearly that variety 
in unity, that inter-dejjendance of all existing things, which has been and ever wUl be the great theme 
of admii-ation to the highest minds. This it is which gives a dignity to the sincere study of the, 
apparently, most trifling objects in natm'c ; no one can ascertain any single fact, nor record any carefully 
made observations, even on the most minute or obsciu'e of Nature's works, without doing some service 
to the progress of human knowledge ; for since the world is one great whole, of which every particle 
has its appointed place and ofiice, its individual existence, and its influence on aU the other parts, — by 
which it is itself in like manner influenced, — all must be clearly made out before an exact knowledge 
can be acquii'ed of entire characters of any one part. Knowledge has now attained to such a vast extent, 
that one mind can scarcely hope to travel over all its provinces, and make personal acquaintance with its 
individual features ; but, as laiowledge extends, it also becomes simplified by generalization ; it is not, 
therefore, so hard a task to acquire a tolerable knowledge of the essential principles of each department, 
while the desu-e for facts and particulars may be gratified in the study of one particular subject. I 
hope to be able to unite, a general outline of vegetable physiology such as it is desu'able that all 
educated persons should possess who lead a coimtry Kfe, with just so much special illustration as may 
give a dii'ect practical character to the pictm-e of facts, suSicieutly interesting to indicate how great a 
fund of entertaining and useful information may be obtained by a personal investigation into the more 
abstruse questions of the science. 
