THE CAUSES OF FLUCrUiTIOSS IX TUEGESCESCi;
which the sparsely distributed stomala are present. Only a little watery fluid had
escaped at this tine, and that seldy from the cat extremity of the shoot. On the
feUowmg mei-ning the uncut surfaces were uniYersally coated by a dry, readily detached,
chalky white layer of concrete latex. Veiy little wateiy cell-sap could have escaped'
as, oTcn after tho dry latex had all been carefully nibbed off, the shoot showed
a loss of only 0-41 gi-ammes in weight. The cut sm-faee of the pith was, however,
slightly depressed, and any section or slight pressure of the epidermis o( the intact
surfaces was followed by abundant exudation of clear fluid. Microscopical sections of the
tissues showed the ramified milk tubes in a more or less shi-unken condition, with
theii- walls often thrown into longitudinal wiinkles, giving them a finely striate appearance,
and their abundantly nucleated protoplasmic lining contracted. The m-inkling
of the tubes and the recession of the protoplasm from the walls are phenomena
which arc no doubt to be ascribed to the action of the reagents employed in staining
and mounting the preparations; but the eutu-e results of the experiment clearly show
that the high state of tnrgescencs nomially present in the laticifcrous system in such
cases is no mere passive engorgement due to extraneous pressure exerted by sm-rounding
turgid tissue elements, as Sachs seems to imply.« For, wore it due to any such agency"
exposure to anesthetic inauences ought certainly not to have given rise to any exudation
of latex, seemg that its tendency is to give rise to diminished turgesconce generally,
and tlierefore to diminished pressure on the milk tubes. Tile fact that the tiihes are
provided with a continuous protoplasmic lining (plate III. fig. 1} is in itself sufiicient to
indicate that the conditions of turgeseence within them must be influenced by intrinsic
agencies, and the fact that exudation of latex procedes that of exudation of cell-sap would
appear to inply that such agencies are really the main determinant of the exti-emely
high turgeseence which normally prevails. What would appear to be the only satisfactory
explanation of the phenomena is that both tho laticiferous tubes and the ether living
tissue elements are in a state of active turgesccuce, but that tho turgidity in the former
is higher than that in the latter, so that, on tho general depression of functional actirity
incident on the action of an anajsthetic, latex escapes more quickly than common cell-sap,
and, occupying the intercellular spaces and concreting when it escapes from the stomatic
orifices, prevents the free exudation of the latter. The results of the experiment further
show that, in any continuous system of tubes of this nature, turgesccuce must be interrnptod
at any points where the functional activity of the protoplasm has been depressed
or abolished, such points constituting sites of localiseii leakage from the system.
In the case of tissues like those employed in the above experiments, the demonstration
of the difference between mere saturation and turgesccuce is rendered particularly
plain, owing to the abundant free exudation of fluid which accompanies anajsthesia • but
almost equally striking demonstrations arc forthcoming in cases whore wo employ tissues
in which the cclI-sap contains coloured matters in solution, as tho escape of these from the
interior of the coll-eavities gives rise to strikmg changes in appearance, especially in the
case of pai-ti-coloured leaves, such as those of many Begonias, &c.
The following experiments illustrate the natui-e of the phenomena in such cases;—
Fx/itrimaf J.—k leaf of Begonia rex, weighing 1-44 grammes, was set in a chloroform
chamber. The upper surface of the leaf was dull green at the margins and centre,
* VorlesuQ};, XI. s. 206. '
IN THE MOTOE OEGA.VS OE LEAVES. 9
and silvery grey ever the intervoning areas; tho loiver one dull red at the margins
and pale green with red vems centrally. Within half an hour very censpicueus change
in colour had occurred, the green originally present in seme parts having almost a S v
disappeared and been replaced by difluso dull rod and g r e y f a n d the t?ssuos i d t the
same ta.e partially collapsed, owing to eommeneing ilaceidity. Three hours afto the
beginmug of t e exper^ent the leaf was quite flaccid, the tissues throughout be n ,
ranslucent and evidently soaked with fluid. A mere trace of free exudation Tad
however, occurred »» that the loss in weight amounted to only 0-04 grammes Jh
disappearance of the green colour eriginally present in seme p a L of the sur ce wa
no doubt pai-tly duo to yellowing of the chlorophyll under the influence of the chanl
m the tissue incident on the action of the chloroform vapour; but to a much g r e aL
extent to the escape and gmeral diffusion of tho red colouring matter normally L i t ed
to tho interior of the cells in certain areas of the inferior surface.
y / . ^ A leaf of B.goni, was set in a chloroform-chamber
The leaves m l„s species are uniformly dull green above and dull red beneath. The
leaf very rapidly became flaccid, and at the same time tho upper surface became diffusedly
reddened due to escape of the coloured fluid from the cells of the lower surface a^d its
general diffusion through tho inlercellular spaces.
E.r.ri,unt UI.-A leaf of Be„nia „.r, coloured like that employed in the first
experimeut, was set m a chloroform-chamber. Wifhin one quarter of an hour the n,argi„
of ho upper surface had begun to redden, and shortly afterwards the entii-e suriaco
gradua y became dUusedly red, the leaf at the same time becoming flaccid and collapsed
As in the previous experiments, the entire tissue became translucent and soaked and the
surfaces moist, but there was no massive discharge of liquid.
I V . ^ A leaf of B^sonia coloured like the former ones, was set in an
alcohol chamber. Withm twenty minutes traces of reddening appear-ed in patches on the
margms of the upper surface, and at the close of an hom- the whole of ti,o upper surface
was n-regulariy blotched with patches of reddish and pale emerald green. On the
followmg day the leaf was moist, translucent, red at the margins and centre, and reddish
g«en m the intermediate, originally grey, area of the upper surface. The colouring was
a l i o throughout the entire thickness of the lamhia. Flaeeidity did not set in so rapidly
or bocomo so highly developed as in the cases in which chloroform was employed the
differences ni this respect and in coloration being no doubt due to the fact that whflst
chlero onn has no affinity for water and no appreciable solvent power for chlorophyll,
alcoho IS Inghly endowed with such properties, so that under its influence we have
both diffusion of the chlorophyll green and less accumulation of water in the tissues
generally. The red colour of the celhsap in these cases is apparently unafl'eotcd by tho
cl,augcs accompanying anesthesia, a phenomenon contrasting strongly with what we
find occurrmg in the case of tho colour of red petalino tis,sucs under similar circumstances,
and no doubt eonnected with tho high permanent acidity of tho fluid
Whilst the changes occurring in fhe living elements of the tissues under tho taflnenco
of anicsthefics lead to a diminution in their retentive power for fluids, and a consequent
loss of turgidity, the watei-eonducting power of tho dead elements of the wood remains
AKN. HOY. B O I . GAUD. CALCUTTA VOL, V I.