THE CAUSES OF FLUCTUATIONS IN TUHGESCENCE
brownisli olive tint. At this time it weighed 5-73 grammes, which, as tlio Huid of tlie
exudation is practically of the same specific gravity as water, indicated a loss of 0-81c.c,
of fluid. It was returned to the chamber, and on the following morning it was quite
flamd and weigiied only 5-42 grammes, corresponding to a total loss of M2c.c. of
fluid during the course of the experiment.
Experiment //.—A leaf weighing 8'73 grammes was set in a chloroform-chamber.
Abundant exudation appeared on the surface within five minutes, and, after six minutes'
exposure, large pools of fiuid had already formed at some points. It was now geutly
wiped, and when weighed was found to be only 7-62 granmies. Having been thoroughly
washed, it was next set in a common moist chamber, wdth the cut extremity of the petiole
immersed in water. Active exudation continued to occur, and foui- and a half hours after
tho beginning of the experiment it was quite flaccid, of a dull, yellowish, olive colour
and weighed only 6-G7 gxammes, equivalent to a total loss of 2-Obc.c. of tluid, and to
a loss of 0-95 after removal from the chloroform-chamber and subjection to the influence of
a saturated atmosphere and free supply of water. It was returned to the moist chamber,
and cn the following morning was found to have sustained an additional loss of 0-34
of fluid.
Ezperimeni I l l . - k leaf weigliing 7-46 gTanmies was placed in a chloroform-chamber
for two minutes and then transferred to a simple moist one, with the cut end of the
petiole immersed in water. In three minutes from the beginning of the experiment
visible exudation was present, and three hours later the surface was everywhere
conspicuously moist, and at one point there was a small pool of fluid. On the followin-''
morning it had quite recovered and weighed 7-52 grammes. In this ease we have im
example of the results following mere temporary depression of protoplasmic activit}-, as
in the two previous ones we had examples of those attending its complete abolition.
Experiment IV.—Two leaves, neither of them being very turgid, were set in a
chloi-oform-chamber. At the end of three hours' exposure they were both quite flaccid
and discoloui-ed. The loss in weight in one (a) amounted to 0-81 grammes and- in the
other (5) to 1-02 grammes. They were now set in a common moist chamber, [a) being
totally immersed in water, and (¿) being set with the cut end of the petiole immersed.
On the following morning (a) showed a farther loss of 0-33 gi-ammes and (¿} of 0'36
grammes, but as (i) was originally heavier tiian (u) by 1-33 grammes, the relative loss
in the latter, although totally submerged in water, was greater tlian that in (i), wliich
V.-&S only subjected to the influence of a saturated atmosphere.
Experiment V.— A leaf, weighing 5*12 grammes, set in a chloroform-chambcr, began to
show visible exudation in the course of six minutes, and at the close of ten minutes had
discharged large pools of fluid. It was now removed and carefully dried, and on being
weighed showed a loss of 0 28 grammes. It was next at once submerged in water, and
on the following morning was rjiiite flaccid, of a yellowish colour, and sliowed an additional
loss in weight of 0-74 grammes. This conclusively shows that complete submersion
produces no appreciable effect on the loss of fluid attending the action of anajsthetics on
living tissues; for the total loss of weight here amounted to nearly 20 pel' cent, of tlie
original Aveight of the leaf, which is much liiglier than that whicli often oeeurs where
the tissues are not submerged.
IN THE MOTOE 0BGAN3 OF LEAVES. 7
Eiperimmt FX^Two leaves, neighing together 36 grammes, were sot in a collecting
gla.5s funnel over a recoiver in a chloroform-chamber. On the following day they weighed
32-01 grammes, and a considerable quantity of a yellowish, strongly acid fluid with a
spocfic gravity of 1030, had accumulated in the receiver. They remained for twentyfour
hours longer in the chamber, and at the end of the c-Nperiment had sustained a
total loss in weight of 4-SG gramme.s, or 13-5 per cent.
Fxporimmt VII.—A largo loaf, weighing 88 gi'ammes, was suspended freo over a
collecting funnel, with a view, as far as possible, to avoid maceration of the tissues by the
exudation, and set in a chloroform-chamber. It showed the usual phenomena of free
exudation and change of colour, and ultimately lost 14-09 per cent, of its original weight
' " ' l O o T ' ^ ' ^ yallowish fluid which collected in the receiver had a specific gravity
The amount of free exudation taking place in leaves of this plant, and probably of
other species also, varies greatly with their age. Young leaves yield mueli less and
consequently sustain much less loss in weight than old ones, this being no doubt partly
due to the intercellular spaces in the former being relatively considerably larger and
affording more accommodation for tho fluid on its escape from the interior of the c^lls.
Exferimcnt Vlll.—k leaf set in an alcohol chamber began to sweat within
twenty-throo minutes, and in the course of three hours had exuded large pools of fluid
On the following day it was of a yellowish olive colour, diyish and brittle in textnie
and showed a loss of 25-06 per cent, in total wei"ht. '
B.—Bryophyllum calycinum.
&p,nm,nt / . - A leaf, weighing 6-44 grammes, was placed in a chloroform-chamber
Within the course of twenty minutes the under surface had assumed a darker green tint
than It had originally, due to displacement of air from tho intercellular spaces and its
substitution by liquid escaping from the interior of the colls, and at the same time free
exudation appeared on the sui-face in the form of minute di-ops situated at definite points
along the margins. A little later e.xudation also manifested itself over tho upper surface
generally; here, however, at no particular points, but merely showing a tendency to
distribution over the course of the veins. Two hours after tho beginning- of the experi
ment, tho leaf was throughout of a pale yellow colour and had lost 0-13 grammes in
• weight The relatively small loss of weight and the rapidity of complete discolom-ation
chai-aetoi-Ming this experiment as compared with those in which Kalanchoe leaves were
subjected to smiilar treatment are doubtless to be accounted for as the result of the
presence of a relatively extensive intercellular system, which on tho one hand aflorded
comparatively largo accommodation for the liquid escaping from the interior of tho cells
and on tho other brought the latter more readily into relation to tho aniBsthetic.
C.—Euphorbia antiquorum.
E.f,nmm, / . - A sheet, weighing 11-26 grammes, was set in a cUoroform-ehamber.
Within an hour and a half the entire uncut surfaces eame to present a peculiar greyish
tmt, due to the o.xudation of minute di-ops of latex into all the depi-cs,sions in