the organisms and organic functions of living 
animals, and it then may be more strictly desig- 
nated vegetable physiology. Yet the two defi- 
nitions so run into each other as to be of little 
or no use for any purpose of either practice or 
theory ; and we therefore may follow them in- 
differently—now the one and now the other—in 
all that we have to say. 
The philosophers of ancient Greece and Rome 
had no notions of vegetable physiology which 
are worth recording; and even the philosophers 
of modern Europe down to the time of Bacon 
continued unacquainted with both the anatomy 
of plants and all the true principles of vegeta- 
tion. Dr. Hooke, who published in 1667, and 
who examined wood-charcoal and saw the small 
cells and the opening of the spiral vessels, was 
the first person who applied a microscope to the 
examination of the structure of plants; and Dr. 
Grew, an English physician, and Malpighi, an 
Italian anatomist, both of whom published in 
1671, were the first observers who conducted 
such searching and extensive investigations by 
dissection and microscopical examination as 
either to lay a true foundation for phytological 
science, or to amass any considerable materials 
for rearing its superstructure. ‘They had no 
mutual intercourse, and yet their experiments 
and observations are so nearly alike that the one 
might seem copied from the other. The charac- 
teristics of both are minute and accurate obser- 
vation, careful experiment, and cautious deduc- 
tion from a large collection of instances. Hence 
we find that no organ of the plant escapes their 
inspection ; roots, trunks, branches, leaves, flow- 
ers, fruits with their appendages, are all sub- 
jected to the most rigid and minute scrutiny, 
as well as those parts and organs which are dis- 
coverable only by the dissection or anatomy of 
the plant,—the pith, the wood, the bark, the 
epidermis, together with the fibres, tubes, or 
membranes into which they are further separ- 
able. This enquiry is followed by a careful en- 
quiry into the respective uses of each, in the 
economy of vegetation,—which is ascertained by 
watching with the most unwearied assiduity the 
phenomena of vegetable life,—the functions of 
the several organs of the plant,—the ‘latens 
processus nature, in casu ubi fit inquisitio ex 
quibus initiis, et quo modo et quo processu herb 
generuntur, a primis concretionibus succorum in 
terra, a seminibus, usque ad plantam formatam, 
cum universa illa successione motus, et di- 
versis et continuatis nature nixibus.’” Many 
distinguished philosophers, from the latter part 
of the 17th century down to the present age, 
particularly Ray, Camerarius, Geoffrey, Vaillant, 
Linnzus, Hales, Bonnet, Duhamel, De la Baisse, 
Cotta, Van Marum, Mustel, Hedwig, Spallan- 
zani, Sprengel, Treviranus, Link, Rudolphi, Mir- 
bel, Knight, Kieser, Dutrochet, Amici, Brong- 
niart, and Brown, followed in the footsteps of 
Grew and Malpighi and in those of one another, 
VEGETABLE PHYSIOLOGY. 
963 
each contributing new materials to phytological 
science, or correcting the observations of pre- 
decessors, till the whole structure and organic 
economy of a plant, and even of every part of it, 
have become almost as completely known as 
those of the highest orders of vertebrated ani- 
mals, and till either clear notions or luminous 
and consistent theories have been obtained upon 
such topics as the processes of nutrition and assi- 
milation, the offices of the spongioles and the 
stomata, the use of the several kinds of cells and 
vessels, the structure and development of seeds, 
the descent of the radicle and the ascent of the 
plumule, the peculiarities of root and stem and 
leaves, the several nature of bark and wood and 
pith, the differences of secretion and excretion, 
the ascent of the sap and descent of the cam- 
bium, the elaboration of liquid from the root 
with gases fromthe leaves, the origin of buds 
and branches, the irritability and vital econo- 
mics of the general system, and even the obscure 
and mysterious process of vegetable fecundation. 
The early phytologists alluded chiefly to orga- 
nic phenomena, and but slightly to functional, and 
not at all to chemical or to vito-chemical. “The 
first experimenters,” says Keith, “seem to have 
had in view nothing beyond the mere analysis 
of their constituent parts, or rather of their me- 
dical properties,—which they endeavoured to 
ascertain by means of the processes of infusion, 
decoction, evaporation, distillation, and combus- 
tion, torturing the vegetable subject in every 
possible way and making much use of the cruci- 
ble. It cannot be said that their researches 
were altogether unprofitable; but certainly they 
did nothing to elucidate the phenomena of vege- 
tation. The key to that mystery may be said to 
have been first found by Priestley, when about the 
year 1771 he discovered the extrication of oxy- 
gen gas, by the leaves of plants, when exposed 
under the water to the rays of the sun. The 
path thus opened up was afterwards successfully 
explored by Ingenhouz and Senebier, who ex- 
tended their researches to a variety of other 
phenomena; and from that time chemical phyto- 
logy has continued to attract the notice of al- 
most all chemists of distinction; among whom 
we may particularly mention Lavoisier, Four- 
croy, Vauquelin, Gay Lussac, and Thenard, in 
France,—and in this country, Chenevix, Thom- 
son, Ellis, and Davy. But the individual who, 
after Priestley, has perhaps the strongest claim 
to originality in these investigations, is Saussure 
the younger, who, in the true spirit of the Ba- 
conian philosophy, has watched and investigat- 
ed, not merely the phenomena of vegetable life, 
but even the phenomena of vegetable death and 
decomposition, demonstrating the peculiar and 
indispensable agency of oxygen in the germina- 
tion of the seed,—the absorption of moisture by 
the root,—its elaboration in the leaf, by the al- 
ternate inhalation and extrication of oxygen and 
of carbonicacid gas, by night and by day,—the de- 
