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see that the arrangement of the capsule in each species is that most
suitable to the general habit of the plant.

In the true geraniums again, as for instance in the herb-robert
(Fig. 6), after the flower has faded, the central axis gradually elon-
gates (Fig. 6, c, d). The seeds, five in number, are situated at the
base of the column, each being inclosed in a capsule, which terminates
upward in a rod -like portion, which at first forms part of the central
axis, but gradually detaches itself. AVhen the seeds are ripe the ovary
raises itself into an upright position (Fig. 6, e) ; the outer layers of
the rod-like termination of the seed-capsule come to be in a state of
great tension, and eventually detach the rod with a jerk, and thus
throw the seed some little distance. Fig. 6, /, represents the central
rod after the seeds have been thrown. In some species, as for instance
in Geranium dissectum, Fig. 7, the capsule-rod remains attached to
the central column, and the seed only is ejected.

It will, however, be remembered that the capsule is, as already
observed, a leaf folded on itself, with the edges inward, and in fact
in the geranium the seed-chamber opens on its inner side. You




Diagram. Fig. 7.— Geranittm dissectum. a, just before throwing seed ; 6, just after throwing
seed ; c, the capsule still attached to the rod ; d, the seed.



will, therefore, naturally observe to me that, when the carpel bursts
outward, the only effect would be that the seed would be forced
against the outer wall of the carpel, and that it would not be ejected,
because the opening is not on the outer but on the inner side. Your
remark is perfectly just, but the difficulty has been foreseen by our



ON FRUITS AND SEEDS.



165



geraniums, and is overcome by tliem in different ways. In some species,
as for instance in Geranium dissecticm, a short time before the dehis-
cence, the seed-chamber places itself at right angles to the pillar (Fig,
7, a). The edges then separate, but they are provided with a fringe
of hairs, just strong enough to retain the seed in its position, yet suffi-
ciently elastic to allow it to escape when the carpels burst away, re-
maining attached, however, to the central pillar by their upper ends
(Fig. 7, f).

In the common herb-robert (Fig. 8), and some other species, the
arrangement is somewhat different. In the first place, the whole
carpel springs away (Fig. 8, b and c). The seed-chamber (Fig. 8, c)
detaches itself from the rod of
the carpel (Fig. 8, b), and when
the seed is flung away remains
attached to it. Under these
circumstances it is unnecessary
for the chamber to raise itself
from the central pillar, to which
accordingly it remains close un-
til the moment of disruption
(Fig. 6, e). The seed-chamber
is, moreover, held in place by
a short tongue which projects a
little way over its base ; while,
on the other hand, the lower
end of the rod passes for a
short distance between the
seed -capsule and the central
pillar. The seed -capsule has
also near its apex a curious tuft
of silky hair (Fig. 8, c), the use
of which I will not here stop to
discuss. As the result of all this complex mechanism, the seeds when
ripe are flung to a distance which is surprising when we consider how
small the spring is. In their natural habitat it is almost impossible
to find the seeds when once thrown. I, therefore, brought some into
the house and placed them on ray billiard-table. They were thrown
from one end completely over the other, in some cases more than
twenty feet.

Some species of vetch, again, and the common broom, throw their
seeds, owing to the elasticity of the pods, which, when ripe, open sud-
denly with a jerk. Each valve of the pod contains a layer of woody
cells, which, however, do not pass straight up the pod, but are more or
less inclined to its axis (Fig. 9). Consequently, when the pod bursts
it does not, as in the case of Cardamine, roll up like a watch-spring,
but twists itself more or less like a corkscrew.




Fig. 8.— Geranium Robebtianum. a, jnst
fore throwing the seed ; b, the red ; c, the seed
enclosed in the capsule.



i66



THE POPULAR SCIENCE MONTHLY.



I have mentioned these species because they are some of our com-
monest wild flowers, so that during the summer and autumn we may,
in almost any walk, observe for ourselves this innocent artillery.
There are, however, many other more or less similar cases. Thus the
squirting cucumber [Momordica elaterium), a common plant in the
south of Europe, and one grown in some places for medicinal pur-
poses, effects the same object by a totally different mechanism. Tlie





Fig. 0.— Vicia sepium. The line a b shows
the direction of the woody fibres.



mi

-The Squirting Cucumber (Momordica
elateriwn.)



fruit is a small cucumber (Fig. 10), and -when ripe it becomes so gorged
with fluid that it is in a state of great tension. In this condition a
very slight touch is sufiicient to detach it from the stalk, when the
pressure of the walls ejects the contents, throwing the seed some dis-
tance. In this case, of course, the contents are ejected at the end by
which the cucumber is attached to the stalk. If any one touches one
of these ripe fruits, they are often thrown with such force as to strike
him in the face. In this the action is said to be due to endosmosis.

In Cyclanthera, a plant allied to the cucumber, the fruit is un-
symmetrical, one side being round and hairy, the other nearly flat and
smooth. The true apex of the fruit, which bears the remains of the
flower, is also somewhat eccentric, and, when the seeds are ripe, if it
is touched even lightly, the fruit explodes and the seeds are thrown
to some distance. The mechanism by which this is effected has been
described by Hildebrand. The interior of the fruit is occupied by
loose cellular structure. The central column, or placenta, to which
the seeds are attached, lies loosely in this tissue. Through the solution
of its earlier attachments, when the fruit is ripe, the column adheres
only at the apical end, under the withered remains of the flower, and
at the swollen side. When the fruit bursts, the placenta unrolls, and



Oy FRUITS AND SEEDS.



167



thus hui'ls the seeds to some distance, being even itself sometimes also
torn away from its attachment.

Other cases of projected seeds are afforded by Hura, one of the
Euphorbice, Collomia, Oxalis, some species allied to Acanthus, and by
Arceuthobium, a plant allied to the mistletoe, and parasitic on juni-
pers, which ejects its seeds to a distance of several feet, throwing them
thus from one tree to another.

Even those species which do not eject their seeds often have thera
so placed with reference to the capsule that they only
leave it if swung or jerked by a high wind. In the
case of trees, even seeds with no special adaptation
for dispersion must in this manner be often carrii I
to no little distance ; and to a certain, though less
extent, this must hold good even with herbaceous
plants. It throws light on the (at first sight) curious
fact that in so many plants with small, heavy seeds,
the capsules open not at the bottom, as one might
perhaps have been disposed to expect, but at the
top. A good illustration is afforded by the well-
known case of the common poppy (Fig. 11), in
which the upper part of the capsule presents a
series of little doors (Fig. 11, a), through which,
when the plant is swung by the wind, the seeds
come out one by one. The little doors are protected
from rain by overhanging eaves, and are even said
to shut of themselves in wet weather. The genus
Ca?}i2)am(la is also interesting from this point of
view, because some species have the capsules pen-
dent, some upright, and those, which are upright open at the top,
while those which are pendent do so at the base.

In other cases the dispersion is mainly the work of the seed itself.
In some of the lower plants, as, for instance, in many sea-weeds, and in
some allied fresh- water plants, such as Vaucheria, the spores * are cov-
ered by vibratile cilia, and actually swim about in the water, like in-
fusoria, till they have found a suitable spot on which to grow. Nay,
so much do the spores of some sea-weeds resemble animals, that they are
provided with a red " eye-spot " as it has been called, which, at any
rate, seems so far to deserve the name that it appears to be? sensitive
to light. This mode of progression is, however, only suitable to water-
plants. One group of small, low-organized plants {Marchantia) develop
among the spores a number of cells with spirally thickened walls,
Avhich, by their contractility, are supposed to disseminate the spores.
In the common horse.-tails {Equisetum), again, the spores are pro-
vided with curious filaments, terminating in expansions, and known

* I need hardly observe that, botanically, these are not true seeds, but rather motile
buds.




Fig. 11.— Seed-head op
VovPY (Papaver.)



i68 TEE POPULAR SCIENCE MONTHLY.

as " elaters." They move with great vigor, and probably serve the
same purpose.

In much more numerous cases, seeds are carried by the wind. For
this, of course, it is desirable that they should be light. Sometimes this
object is attained by the character of the tissues themselves, sometimes
by the presence of empty spaces. Thus, in Valerianella auricula, the
fruit contains three cells, each of which would naturally be expected
to contain a seed. One seed only, however, is developed, but, as may
be seen from the figure given in Mr. Behtham's excellent " Handbook
of the British Flora," the two cells which contain no seed actually be-
come larger than the one which alone might, at first sight, appear to be
normally developed. We may be sure from this that they must be of
some use, and, from their lightness, they probably enable the wind to
carry the seed to a greater distance than would otherwise be the case.

In other instances the plants themselves, or parts of them, are rolled
along the ground by the wind. An example of this is afforded, for
instance, by a kind of grass {Spinifex squarrosus), in which the mass
of inflorescence, forming a large round head, is thus driven for miles
over the dry sands of Australia until it comes to a damp place, when
it expands and soon strikes root.

So, again, the Anastatica hierochxmtica, or "rose of Jericho," a
small annual with rounded pods, which frequents sandy places in
Egypt, Syria, and Arabia, when dry, curls itself up into a ball or round
cushion, and is thus driven about by the wind until it finds a damp
place, when it uncurls, the pods open, and sow the seeds.

These cases, however, in which the seeds are rolled by the wind
along the ground are comparatively rare. There are many more in
which seeds are wafted through the air. If you examine the fruit of
a sycamore you will find that it is provided with a wing-like expansion,
in consequence of which, if there is any wind when it falls, it is, though
rather heavy, blown to some distance from the parent tree. Several
cases are shown in Fig. 12 : for instance, the maple, a, sycamore, b,
hornbeam, d, elm, e, birch, /, pine, g, fir, h, and ash, i, while in the lime,
c, the whole bunch of fruits drops together, and the " bract," as it is
called, or leaf of the flower-stalk, serves the same purpose.

In a great many other plants the same result is obtained by flat-
tened and expanded edges. A beautiful example is afforded by the
genus Thysanocarpus, a North American crucifer ; Th. laciniatiin has
a distinctly winged pod ; in T. curvipes the wings are considerably
larger ; lastly, in T. elegans and T. radians the pods are still further
developed in the same direction, T. radians having the wing very
broad, while in T. elegant it has become thinner and thinner in places,
until at length it shows a series of perforations. Among our common
wild plants we find winged fruits in the dock {Biimex) and in the
common parsnip {Pastinaca). But though in these cases the object
to be obtained — namely, the dispersion of the seed — is effected in a



ox FRUITS AND SEEDS.



169



similar manner, there are differences which might not at first be sus-
pected. Thus in some cases, as, for instance, the pine, it is the seed
itself which is winged ; in 77ilaspi ai'vense it is the pod ; in Entada,
a leguminous plant, the pod breaks up into segments, each of which is




Fig. 12.— a, maple ; b, sycamore : <•, lime ; rf, hornbeam ; e, elm ; /, birch ; g. pine ; h, fir ; j, ash.

winged ; in ^issolla the extremity of the pod is expanded into a flat-
tened wing ; lastly, in the lime, as already mentioned, the fruits drop
off in a bunch, and the leaf at the base of the common flower-stalk, or
" bract," as it is called, forms the wing.

In Gouania retinaria of Rodriguez the same object is effected in
another manner ; the cellular tissue of the fruit crumbles and breaks
away, leaving only the vascular tissue, which thus forms a net inclos-
ing the seed.

Another mode, which is frequently adopted, is the development of
long hairs. Sometimes, as in Clematis, Anemone, Dryas, these hairs
take the form of a long, feathery awn. In others the hairs form a tuft



170 THE POPULAR SCIENCE MONTHLY.

or crown, which botanists term a pappus. Of this the dandelion and
John Go-to-bed-at-noon, so called from its habit of shutting its flowers
about mid-day, are well-known examples. Tufts of hairs, which are
themselves sometimes feathered, are developed in a great many Com-
posites, though some, as, for instance, the daisy and lapsana, are with-
out them : in some very interesting species, of which the common
Thrincia hirta of our lawns and meadows is one, there are two kinds
of fruits, as shown in Fig. 13, h, one with a pappus and one without.
The former are adapted to seek " fresh woods and pastures new," while
the latter stay and perpetuate the race at home.

A more or less similar pappus is found among various English
plants — in the Epilobium (Fig. 13, a), Thrincia (Fig. 13, h), Tamarix




Fig. 13.— a, willow herb (Epilobium) ; b, two forms of seed of Thrincia hirta ; c, Tamarix ; rf, wi
low {Salix) ; e, cotton grass {Eriophorum) ; f, bulrush ( Typha).



(Fig. 13, c), willow (Fig. 13, d), cotton-grass (Fig. 13, e), and bulrush
(Fig. 13,/) ; while in exotic species there are many other cases — as, for
instance, the beautiful oleander. As in the wings, so also in that of
the pappus, it is by no means always the same part of the plant which
develops into the crown of hairs. Thus in the Valerians and Com-



SUNSTROKE AND SOME OF ITS SEQUELS. 171

posites it is the calyx ; in the buh-ush the perianth ; in Epilobium the
crown of the seed ; in the cotton-grass it is supposed to represent the
perianth ; while in some, as, for instance, in the cotton-plant, the
whole outer surface of the seed is clothed with long, hairs. Some-
times, on the contrary, the hairs are very much reduced in number, as,
for instance, in some species of JEschynanthus, where there are only
three, one on one side and two on the other. In this case, moreover,
the hairs are very flexible, and wrap round the wool of any animal
with which they may come in contact, so that they form a double
means of dispersion.

In other cases seeds are wafted by water. Of this the cocoanut
is one of the most striking examples. The seeds retain their vitality
for a considerable time, and the loose texture of the husk protects
them and makes them float. Every one knows that the cocoanut is
one of the first plants to make its appearance on coral islands, and it
is, I believe, the only palm which is common to both hemispheres.

The seeds of the common duckweeds {Lemna) sink to the bottom
of the water in autumn, and remain there throughout the winter ; but
in the spring they rise up to the surface again, and begin to grow. —
Fortnightly Revieic.

[ 7'o be continued.'\



SUNSTROKE AND SOME OF ITS SEQUELS.

By Sik JOSEPH FAYRER, M. D., F. R. S. ~

TTNDER the designations of sunstroke, coup-de-soleil, heat-apo-
vJ plexy, heat-asphyxia, thermic fever, ardent fever, insolation, and
others, are included certain pathological states which, though differing
from each other materially, are not unfrequently confounded.

1. There is simple syncope from exhaustion caused by heat.

2. A condition analogous to shock, due to the action of the direct
rays of a powerful sun on the brain and cord ; the nerve-centers, espe-
cially the respiratory, are affected ; respiration and circulation rapidly
fail, and death may result ; recovery is frequent, though not always
perfect.

3. Overheating of the whole body, blood, and nerve-centers, either
from direct exposure to the sun's rays, or, more frequently, to a high
temperature out of them ; causing vaso-motor paralysis and intense
pyrexia (fever) ; respiration and circulation fail, and asphyxia fol-
lows. Recovery frequently occurs, but is often incomplete, owing
to structural changes in the centers, giving origin to a variety of
symptoms indicative of lesions of a grave character.

The cases of simple exhaustion and syncope may occur during



172 THE POPULAR SCIENCE MONTHLY.

great fatigue or over-exertion, or when there is depression of vital
power from any cause during exposure to a high temperature. There
^s depression of nerve-force and of muscular power ; the skin is pale,
cold, and moist, the pulse feeble. Death may occur in this state from
failure of the heart ; but complete recovery more frequently occurs.
Asphyxia and apnoea (stoppage of the breath) may come on after pre-
monitory symptoms of depression and weakness, during exposure of
the head and spine to the direct rays of a powerful sun, when the
atmosphere is much heated, and the nervous energy is depressed by
over-fatigue, illness, or dissipation. The brain and respiratory nerve-
centers are overwhelmed by the sudden rise of their temperature, and
respiration and circulation fail.

Recovery, though frequently complete, is sometimes tedious and
occasionally imperfect, ending in serious impairment of health or in-
tellect.

The symptoms of this form of sunstroke are those of sudden and
violent derangement of the nerve-centers, unconsciousness, cold shivers,
feeble pulse ; all the signs of depression, terminating in death by shock ;
or fatal reaction may result with a variety of conditions pointing to
injury to the cerebro-spinal system. In another class of cases there is
ardent fever, the body generally, including the nerve-centers^ is heated
intensely ; this may occur quite independently of the direct action of
the sun's rays. It comes on frequently at night, or in the shade, in a
building or tent, especially in persons who are depressed by fatigue,
bad air, overfeeding, alcoholic stimulants and the consequent depres-
sion, want of rest, illness, and notably when the air is impure from
overcrowding, or from insufficiency of cubic space.

The temperature of the body may rise to 108°-110° ; respiration
and circulation fail ; there are hurried, gasping respiration, great rest-
lessness ; pungently hot skin, sometimes dry, occasionally moist. The
pulse varies ; in some it is full and laboring, in others quick and jerk-
ing ; the head, face, and neck are livid and congested ; the carotid
pulsation is very perceptible ; the pupils, at first contracted, dilate
widely before death. Coma, stertor, delirium, convulsions frequently
epileptiform in character, with relaxation of sphincter, and suppres-
sion of urine — these are the precursors of death by asphyxia, and it
may be that there is cerebral haemorrhage.

Such are the cases to which the term heat-apoplexy is given ; and a
large proportion of the fatal attacks among Europeans in India are so
caused. Recovery may partially occur, to be followed by relapse and
death, or secondary consequences, the result of tissue-change, may
destroy life or impair health and intellect at a later period. The pre-
monitory symptoms of this form of the disease may appear some hours
or even days before the dangerous condition just described supervenes.
There may be general malaise, disordered secretions, profuse and fre-
quent micturition, restlessness, insomnia (sleeplessness), apprehension



SUNSTROKE AND SOME OF ITS SEQUELAE. 173

of impending evil, hurried and shallow breathing, disturbance about
the heart, gasping, giddiness, headache, occasionally nausea or vom-
iting, thirst, anorexi^i (want of appetite), feverishness, which soon
amounts to fervent heat of skin ; the surface may be dry or moist,
the pulse varies ; and these conditions gradually become aggravated
and frequently are worse at night, when the patient passes into a state
of unconsciousness and dies.

The symptoms point to a profoundly distui'bed state of the cerebro-
spinal nerve-centers, and to pathological changes in the organs whose
functions have been so greatly disturbed.

Death is caused by asphyxia and apnoea, and in some cases probably
by cerebral haemorrhage. Recovery is often incomplete, resulting in
permanent impairment of health, and generally in intolerance of heat
and of exposure to the sun. These morbid conditions being due to
heat alone, are liable to occur whenever there is exposure to a high
temperature, whether solar or artificial. Soldiers marching or fight-
ing, when oppressed by weight of clothing or accoutrements, are apt
to suffer either from simple heat-exhaustion or from that form of
insolation which results from direct action of a powerful sun on the
head and spine. Soldiers, laborers, artificers, and people in factories,
heated rooms, hospitals, barracks, tents, and even ships, may suffer
from heat-exhaustion, which may pass into the same dangerous
condition of heat-asphyxia. People in the hay-field, or otherwise
exposed to great heat, especially if they have indulged in excess of
alcoholic stimulants and food, may suffex*. Weak persons with defec-
tive hearts may die in this state of syncope. Soldiers or others, when
exposed to great heat, may drop out of the ranks, fall in a state of
syncope and die on the spot, or pass into a state of coma and die later ;
or they may recover, after being in great danger, with damaged nerve-
centers, and are rendered quite unfit for further service, or even resi-
dence in a hot climate. These cases occur on exposure to the direct
action of the sun's rays when the atmospheric temperature is also high,
and especially when unusual exertion is made, or when the individual
is depressed by previous illness or the exhaustion due to dissipation,
intemperance, or even undue indulgence in stimulants.

But the most serious cases are those that come on under cover by
night as well as by day, and apart from the direct solar rays. Heat
alone, especially when the atmosphere is loaded with moisture so as to
prevent evaporation from the person, is the real cause of the disease.

Vigorous, healthy persons of moderately spare frame, with sound
viscera, and who are of temperate habits, if the atmosphere be pure
and moderately dry, can sustain a great amount of heat. Acclimatiza-
tion has also some influence in conferring toleration. Fresh arrivals
in the tropics are more prone to suffer than those who have become
accustomed to the climate, and have learned how to protect them-
selves. It is well known that a native can bear an amount of sun on



174 THE POPULAR SCIENCE ^MONTHLY.

his bare head and naked body with indifference, ahnost pleasure, that
would rapidly prostrate a European, But when the temperature rises
above a certain standard all succumb, and natives of India suffer and
die like others in numbers every year from loo mama (hot-wind
stroke).

The extent and duration of the tolei-ation of heat depend much on
the vigor of constitution and actual state of health. The refrigerat-
ing powers of the body, when in health, enable it to support a very
high temperature, considerably above that of the blood. Thus, in the
hot winds little inconvenience is felt so long as perspiration is free,
but, when that fails, suffering soon ensues, and the danger is great.

In the fourteenth annual report of the Sanitary Commissioner with
the Government of India, 1877, it is stated that two hundred and
thirty-five cases of heat-apoplexy and sunstroke occurred in the army
in India, of which seventy were fatal. Of those who recover, or rather
do not die, many are permanently injured, and remain invalids for the
rest of life, which is frequently shortened by the changes induced.

No remarkable morbid change is observed in cases where death
has occurred suddenly. The heart may be firmly contracted, and the



Online LibraryD. S. (David Samuel) MargoliouthThe Popular science monthly (Volume 19) → online text (page 22 of 110)