130 
HORTICULTURE AS A SCIENCE. 
it does, provided a due discrimination be made between organized beings endowed 
with the vital principle, and effete decomposing substances, such as earths, stones, 
manures, and dead vegetable matter. 
The investigation therefore of soils, of manures, animal and vegetable, of the 
ashes produced by fire, of water, of atmospheric air, and other airs or gases, 
of gums, resins, oils, and salts, becomes the subject of legitimate chemical inquiry; 
but if chemistry be applied to the investigation of organized living bodies, 
its powers are misdirected, and erroneous conclusions must be the inevitable result. 
On a future occasion, it is proposed to offer a few preliminary remarks eluci- 
datory of the various chemical terms in ordinary use ; this will pave the way 
to the attainment of first or leading principles, and render the amateur and pro- 
fessional gardener acquainted with the meaning of words which he must continually 
meet with, and frequently employ. Some years ago, a series of chemical papers 
appeared in the pages of the Horticultural Register, which will, to a certain extent, 
obviate the necessity of entering upon the detail of analysis ; still it will be desir- 
able to collect together the various articles that form what are termed " tests and 
re-agents," all of which can now be purchased at a very trifling expense, and 
by these a gardener may at once ascertain what chemical salt or product exists in 
the juices of many plants. Thus, in the tasteless sap of the vine, he will in a 
moment be able to prove and exhibit the presence of a very small portion of lime ; 
a circumstance which could scarcely be anticipated by ordinary observers, who still 
must feel astonishment in reflecting upon the conversion of a fluid so utterly void of 
flavour, into, first, the austere sour juice of the green unripe grape ; and, finally, 
into the rich nectar of the mature fruit. 
Yes, Chemistry has its uses, — we mean the Chemistry of the laboratory; 
for by it a great variety of the components of matter can be critically examined, 
and minutely detailed. But when we come to view the operations of the vital 
principle — to consider the agency of light, heat, and electricity, the production of 
the proper juice or cambium, and the distribution of the specific products of indi- 
vidual vegetables, we must speak with the extreme modesty which the intricate 
delicacy of the subject demands, and be very careful how we refer them to pure 
chemistry. 
The late Sir J. E. Smith observed, " We must constantly remember that it " 
(an organized plant) " is not merely a collection of tubes and vessels, holding 
different kinds of fluids, but that it is endowed with life, and consequently able not 
only to imbibe particular fluids, but to alter their nature according to certain laws ; 
that is, to form peculiar secretions ; this is the exclusive property of a living being." 
• The most different and discordant fluids, separated only by the finest film or 
membrane, are kept perfectly distinct while life remains ; but no sooner does the 
vital principle depart, than secretion, as well as the due separation of what has 
been secreted, are both at an end, and the principle of dissolution reigns absolute." 
At this point, but not before, chemical agency commences, and effects the total 
decomposition of the products. 
