562 
VEGETABLE CHEMISTRY. 
pounds with some other substance. It is not 
unlikely that all the vegetable principles may be 
found hereafter to be capable of entering into 
definite compounds with other bodies, and that 
they will be ultimately possessed of the charac- 
ter of acids or bases. But there are a good many 
vegetable principles which, so far as our present 
knowledge extends, do not seem capable of form- 
ing any such definite compounds. Thus caout- 
chouc neither combines with acids nor bases. 
We must consider such bodies as neutral. 
There exist also several groups of bodies which 
have been distinguished by a common name, 
some of which neutralize acids, and therefore 
ought to constitute bases, while others belonging 
to the same group neutralize bases, and there- 
fore ought to constitute acids; while a consider- 
able number of the bodies belonging to the group 
has been so imperfectly examined, that we do 
not know whether they be acids or alkalies. This 
is the case with the group of bodies distinguished 
by the name of volatile oils. Oil of turpentine 
saturates muriatic acid, and therefore is a base; 
while oil of cloves saturates bases, and therefore 
is an acid. But many of the other volatile oils 
have been so imperfectly examined, that we 
could not venture to place them either among 
bases or acids.” “ Nearly all bodies of vegetable 
origin,” says Dr. Turner, “are composed of oxy- 
gen, hydrogen, and carbon; and in a few of them, 
nitrogen is likewise present. Hvery distinct 
compound which exists ready formed in plants, 
is called a proximate or immediate principle of 
vegetables. Thus sugar, starch, and gum, are 
proximate principles. Opium, though obtained 
from a plant, is not a proximate principle; but 
consists of several proximate principles mixed 
more or less intimately with each other. The 
proximate principles of vegetables are sometimes 
distributed over the whole plant, while at others 
they are confined to a particular part. The 
methods by which they are procured are very 
variable. Thus gum exudes spontaneously, and 
the saccharine juice of the maple-tree is obtained 
by incisions made in the bark. In some cases a 
particular principle is mixed with such a variety 
of others, that a distinct process is required for 
its separation. Of such processes consists the 
proximate analysis of vegetables. Sometimes a 
substance is separated by mechanical means, as 
in the preparation of starch. On other occa- 
sions advantage is taken of the volatility of a 
compound, or of its solubility in some particular 
menstruum. Whatever method is employed, it 
should be of such a nature as to occasion no 
change in the composition of the body to be pre- 
pared. The reduction of the proximate princi- 
ples into their simplest parts, constitutes their 
ultimate analysis. By this means chemists as- 
certain the quantity of oxygen, carbon, and hy- 
drogen present in any compound.” See the arti- 
cles Proxtmats Principe, ANALYSIS, and Vrge- 
TABLE Puystonocgy. The methods of analysis 
VEGETABLE PHYSIOLOGY. 
introduced not many years ago by Liebig and 
Dumas opened a new era in vegetable chemistry, 
and suddenly let in upen it an inundation of 
new facts and explanations; insomuch that seve- 
ral hundred new vegetable substances were dis- 
covered in a very brief time by these two distin- 
guished chemists and their pupils, and many of 
the most talented young chemists both on the 
Continent and in Britain were induced to devote 
their main strength to enquiries in that direc- 
tion, and such multitudes of accessions began to 
be made to the knowledge of chemical reactions 
and combinations within the vegetable kingdom 
as speedily raised the study of organic chemistry 
to as broad a platform of investigation and to as 
lofty an influence over economics and the arts 
as that of all the combined departments of the 
general chemistry which had been accumulating 
its resources for centuries. Agricultural che- 
mistry, therefore, which is but one department 
of vegetable chemistry, has already become a 
separate and great science. 
VEGETABLE EXCRETION. See Excretion 
or Puants. 
VEGETABLE EXTRACT. See Exrracr. 
VEGETABLE JELLY. See Prcrin. 
VEGETABLE LIFE. See Organic CoEemistTRy. 
VEGETABLE MARROW. The succada gourd, 
—a variety of the egg-bearing gourd, Cucurbita 
ovifera. It is an annual; and is raised under a 
hand-glass or in a frame, and afterwards trans- 
planted into a warm aspect, and trained to a 
trellis or to some similar support. Its fruit is 
uniformly of a pale yellow colour, and of an 
elliptic-oblong shape; and when full grown, is 
about 9 inches in length and 4 inches in diame- 
ter. It is by far the best of the gourds for culi- 
nary purposes; and, though generally eaten 
when about the size of a hen’s egg, may be used 
at any stage of its growth. When very young, 
it does well to be fried with butter; and when 
half-grown, it is excellent either plain boiled or 
stewed with rich beef-gravy ; and, in either case, 
it requires to be cut into slices. It takes its 
name of vegetable marrow from the peculiar 
tenderness and softness of its flesh. 
VEGETABLE MORPHOLOGY. 
PHOLOGY. i 
VEGETABLE MOULD. See Humtus. 
VEGETABLE PHYSIOLOGY. ‘The science 
which treats of the structure, functions, and 
vital phenomena of plants. It either may be 
understood quite comprehensively as discussing 
all matters which concern living plants, in the 
same wide way in which zoology discusses all 
matters which concern living animals, and it 
then may be more properly called phytology ; or 
it may be taken more limitedly as discussing 
only matters which concern the organisms and 
the organic operations of living plants, irrespec- 
tive of specific habits and chemical constituen- 
cies and external connexions, in the same limited 
way in which animal physiology treats only of 
See Mor- 
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