of slugs and injurious insects; they are, moreover, perfectly
harmless. Some ignorant people, who love to destroy everything, insist
on killing frogs and toads; they say they eat the strawberries in
their gardens. Did you ever examine a frog's or a toad's tongue,
Willy? You never did; then I hope the next frog you catch you will
carefully open his mouth--treat him as if you loved him, as honest
Isaac Walton says--and give me some short account of the structure of
a frog's tongue. "All right, papa," said Willy, "I will bear the
matter in mind. It makes me laugh, though, to think of my examining a
frog's tongue; still I wonder what it is like, and I wish I could at
once catch a frog to see; but we are now again near home, and I must
wait for another walk."
[Illustration]
WALK IV.
MAY.
"Papa," said Willy, "you once told me of a very beautiful little
creature, almost too small to be seen by the naked eye, that lives in
water, and builds its house out of the small particles of clay or mud
that float therein. The bricks are not of the shape of house bricks,
but quite round. Do you not think we can find some of these animals in
the course of to-day's walk? I forget the name of the creature." I
know what you mean; you are speaking of a microscopic animal called
_Melicerta_. "Oh, yes, that is its name, now I remember." I have no
doubt we shall be able to obtain specimens from the canal; so we will
walk along the bank for a short distance and then get into the fields
again. We must take with us a clear wide-mouthed bottle, and we shall
soon see whether we have captured any specimens. These exquisite
little creatures attach themselves to the leaves and stems of
water-plants; they are most readily seen on the finely cut leaves of
the water-buttercup or spiked milfoil. The way to proceed is to place
a tuft of this plant in the bottle and to hold it up to the light, and
we shall soon see whether any Melicertæ are there.
[Illustration: MELICERTA ON WEED.]
Here is plenty of water-buttercup--a very interesting plant
by-the-bye, and one which is subject to much variation; for when it
grows in swiftly flowing water all the leaves are very long and
hair-like, but in still water there are flattened leaves as well, and
the hair-like leaves are not nearly so long. You see it is now in
flower; a beautiful white mass it forms in small still ponds. "Well,
but, papa," said May, "the flowers are white, and I thought all
buttercups were yellow." Nearly all the buttercups have yellow
flowers, but there are two British species which have white blossoms,
namely, this one and the little ivy-leaved buttercup, or crowfoot, as
it is often called, which is found either in the water or near the
water's edge. Though the ivy-leaved crowfoot is generally regarded as
a species, I think it is only a variety of the one we are now looking
at. Now I fish a plant out with my stick and nip off a tuft of
hair-like leaves and pop it into the bottle. Have I anything here? No
doubt the microscope would show countless numbers of minute
animalcules, but I detect no Melicertæ. Let us try again. I nip off
another tuft. There! do you see one, two, three, four little things
sticking almost at right angles to some of the leaves? No, you see
nothing? Well, perhaps not, for your eyes are not so accustomed to
these things as mine are, but I will take out my pocket lens; there,
surely you see that one close to the side of the bottle, do you not?
Oh yes, you see what I mean; well, that is the case or house of a
Melicerta, which animal I will describe to you, and when we get home
we will look at it under the microscope. The case is about the twelfth
part of an inch long and about the thickness of a horsehair, and of a
reddish colour generally, though the colour depends on the nature of
the material out of which the case is made. Let us sit down and put
the bottle on this large stone, and I dare say some of the creatures
will soon show their heads at the top of the tubes, for they are all
indoors now; the disturbance caused in breaking off the bit of weed
and putting it in the bottle has alarmed the Melicertæ, and very
quickly they sunk within their houses of clay.
[Illustration: MELICERTA, ON WEED, MAGNIFIED.]
Now I see one fellow slowly appearing at the top, after the manner of
a chimney-sweeper, but certainly in a much more elegant form. There!
it has unfolded four flower-like expansions, of which the uppermost
are much the largest. The animal shows only the upper part of its
body, and I can see with my pocket lens that it is somewhat
transparent and whitish. But my lens has not sufficient magnifying
power to reveal more, so I must tell you what I have seen of Melicerta
under my compound microscope. Each of these four leaf-like lobes or
expansions is surrounded with very minute hairs, which can move with
great rapidity in all directions; these you will remember are called
"cilia," from the resemblance to _eyelashes_, for which cilia is the
Latin word. The motion caused by these numerous cilia lashing the
water brings currents containing particles of food for the Melicerta,
and materials for his house. Mr. Melicerta "is at once brick-maker,
mason, and architect, and fabricates as pretty a tower as it is easy
to conceive." The mouth is situated between the two large leaflets,
and leads to a narrow throat, in which are the curious jaws and teeth
of the animal. Below the jaws are the stomach and intestine; so you
see the Melicerta, though so minute a creature, has a complex
structure. "You said, papa," remarked May, "that the little creature
makes its own tube; how does it do that?" Upon the upper part of the
head there is a small hollow cup, which is lined with cilia, and
probably also secretes some sticky fluid to make the pellets of clay
adhere together; the particles of clay and mud, having been brought to
the space between the leaflets by the action of the cilia, are
conveyed to this little cup-shaped cavity, and are then worked about
by the cilia within, till a round pellet is formed which completely
fits the cavity. The little creature then bends itself down upon the
tube and deposits the pellet upon it, then it raises itself up again
and proceeds to form another brick, its jaws working all the time. "I
wonder," said Jack, "how the little creature manages to set apart and
put in its proper place the particles required for food and those
required for brick-making; it would be funny if it sometimes made a
mistake and put the clay in its stomach and the food in the brick
machine!" It is curious, indeed, to know how the materials are put in
the proper place; I suppose the Melicerta has the power to change the
direction of the currents and thus to place the particles in their
proper place. By rubbing a little paint, such as carmine or indigo, in
some water and placing a drop upon the glass slide with the Melicerta,
these currents may be readily seen; and I have more than once seen
rows of coloured bricks, red or blue, which the animal moulded and
then deposited on the tube! We will take the bottle home, and if you
have patience I doubt not I shall be able to show you a good deal of
what I have been describing; but you must have patience, for, as an
excellent naturalist has said, "The Melicerta is an awkward object to
undertake to show to our friends, for, as they knock at the door, she
is apt to turn sulky, and when once in this mood it is impossible to
say when her fair form will reappear. At times the head is wagged
about in all directions with considerable vehemence, playing singular
antics, and distorting her lobes so as to exhibit a Punch and Judy
profile."[B]
Hark! what is that bird singing so sweetly and with such animation in
the hedge? Do you hear? It is the dear little sedge-warbler; often,
indeed, heard, but not so often seen, for it is fond of hiding itself
in bushes or sedges. The sedge-warbler, like the migratory warblers
generally, comes to us in April and leaves us in September. How often
have I listened with delight to its music when returning home quite
late at night in summer months! If the bird stops its music for a few
moments, you have only to throw a stone among the bushes and the
singing commences again. I am not clever in describing musical sounds,
and I cannot describe that of the sedge-warbler, nor can I always
distinguish it from the song of its near relative the reed-warbler.
Both imitate the songs of other birds, and their incessant warblings
and babblings at night cause them to be often mistaken for
nightingales. I have generally found the nest of the sedge-warbler on
the ground, on a tuft of coarse grass or sedge; the nest of the
reed-warbler is supported on four or five tall reeds, and is made of
the seed-branches of the reeds and long grass wound round and round;
it is made deep, so that the little eggs are not tossed out when the
reeds are shaken by the high winds.
[Illustration: NEST OF REED WARBLER.]
Hark! there is the cuckoo; how clearly he utters "cuckoo! cuckoo!" He
is not far away. Some people can imitate the well-known note so well
as to deceive the bird and bring it near the place where they are
hiding. Your Uncle Philip only the other day made a cuckoo respond to
him; had the day been calm instead of windy, he would, no doubt, have
induced the bird to come close to us. There he goes with his long
tail, flying something like a hawk. You should remember the rhyming
lines about the cuckoo's visit to this country:
In April,
Come he will.
In May,
He sings all day.
In June,
He alters his tune.
In July,
He prepares to fly.
Come August,
Go he must.
"I think you said, papa," said May, "that it is only the male bird
that utters the cuckoo note; what kind of a voice has the female?" I
have never heard the note of the female cuckoo. Mr. Jenyns says, "The
note of the female cuckoo is so unlike that of the male, which is
familiar to every one, that persons are sometimes with difficulty
persuaded that it proceeds from that bird. It is a kind of chattering
cry, consisting of a few notes uttered fast in succession, but
remarkably clear and liquid." Very curious are the habits of the
cuckoo. Unlike most other birds, they do not pair; you all know, too,
that cuckoos make no nests, but lay their eggs one by one in the nests
of various other birds, such as those of the hedge-warbler, or
hedge-sparrow as it is generally but wrongly called, robin,
white-throat, and other birds. It is probable that the same cuckoo
does not go twice to the same nest to deposit her egg. What a curious
exception is the case of the cuckoo to the instinctive love of their
offspring observable in almost all birds! After the eggs are laid the
parent bird has no further trouble with them; no period of incubation
to bare the breast of the brooding bird; no anxiety about her young
ones, as some idle, wanton lad hunts amongst the trees and bushes,
destroys both nest and eggs, or tortures the helpless fledglings!
"But, papa," said Willy, "how does it happen that the young birds
hatched in the same nest with the young cuckoo always get turned out
of it." The cuckoo, being much the larger and heavier bird, fills up
the greater part of the nest, consequently the smaller fledgling
companions get placed on the sides of the nest, and partially also on
the back of the young cuckoo; when, therefore, the latter stands up in
the nest he often lifts up on his back one of the small companions,
who thus gets thrown headlong to the ground. This seems to me to be
the mode in which the ejection sometimes takes place, till at last the
young cuckoo is left sole possessor of the nest, and of course gets
all the food; at the same time I ought to say that some naturalists
attribute a murderous disposition to the young cuckoo, and say that
the other inmates of the nest are maliciously thrown out. Others,
again, say that the foster birds throw their own young ones out. It
is certain that the young are sometimes treated thus, for they have
been seen on the ground when the young cuckoo was too small to eject
them itself.
[Illustration: CUCKOO.]
"But why do not cuckoos make nests and sit on their eggs like other
birds?" said Jack. Such a question is more easily asked than answered;
nevertheless I hope you will always try to discover reasons for
things. "It is now," writes a celebrated naturalist, "commonly
admitted that the more immediate and final cause of the cuckoo's
instinct is, that she lays her eggs, not daily, but at intervals of
two or three days; so that if she were to make her own nest and sit on
her own eggs, those first laid would have to be left for some time
unincubated, or there would be eggs and young birds of different ages
in the same nest. If this were the case the process of laying and
hatching might be inconveniently long, more especially as she has to
migrate at a very early period, and the first hatched young would
probably have to be fed by the male alone." The cuckoos come to this
country about the middle of April; the male birds arrive before the
females. Whether this arrangement is ungallant conduct on the part of
the gentlemen birds, who prefer to come alone, or whether, just when
the gentleman cuckoo is ready and almost impatient for a start, her
ladyship has all at once discovered some important matter that ought
to be finished before leaving the country, some adjustment of her
dress, some tiresome feather that will ruffle itself up in spite of
every effort to keep it smooth, I know not, but the fact remains, that
my Lord and Lady Cuckoo do not travel together. Let us suppose that
both sexes have arrived in this country, we will say about the 23rd of
April. It is natural they want a little time to look about them; at
any rate, no egg is ready for being sat upon till some weeks after the
arrival of the birds, say the 15th of May. The eggs require fourteen
days' setting before they are hatched; this brings the date to the
29th of May. The young ones will require three weeks in the nest and
constant feeding all the time; we now arrive at about the 20th of
June, when the young ones would be ready to leave the nest. But they
want five weeks' more feeding by the parents, after they leave the
nest, before they are able to provide for themselves; this would bring
the date to about the 25th of July, when there is hardly a parent bird
in the country; they have left for other parts of the world. "Oh! but,
papa," said Willy, "you said in the lines you told us to remember--
In July,
He prepares to fly.
Come August,
Go he must.
And now you say the cuckoos leave before the end of July. I think you
must have made a mistake somehow." I am glad that you have found out
the error, if it is one. Old rhymes are not always to be trusted; but
I suspect that the couplet "Come August, go he must," means to imply
that the cuckoo does never really stay so late with us. I must not,
however, forget to tell you that it is the old parent birds that leave
us early; young birds remain till September, and even October, but
they have not by that time acquired the cuckoo note. If you ask why
cannot the old cuckoos stay with us a little longer, and then all go
away together as a family party, young and old, in September, instead
of being in such a hurry, I have only to say that it is the fashion
amongst cuckoos, and of course cuckoos, like certain other animals,
must be in the fashion. This is Dr. Jenner's explanation of the
peculiar habits of the cuckoo in respect of its eggs. I am not
prepared to say whether or not it is sufficient to explain them. The
cuckoo's egg is very small when compared with the size of the bird; it
is of a pale grey tinged with red.
"But how does the cuckoo's egg get into some of the nests?" asked
Willy; "for some of the nests in which the cuckoo's egg is found are
too small to allow the cuckoo herself to enter to lay her egg." You
are quite right; I believe it has been proved that the cuckoo lays her
egg on the ground, and carries it in her bill into other birds' nests.
[Illustration: HORSE-TAIL.]
"Oh! papa," said Jack, "what is this curious plant that grows so
abundantly on the grass here? I know it well by sight, but do not know
its name." It is a spike of horse-tail; see how the stem is marked
with lines, and how curiously jointed it is, and quite hollow except
where the joints occur. The fruit is borne at the top of the plant
(_a_); see, as I shake it, what a quantity of dust comes from it; this
dust is the fruit, or spores as they are called; each spore is of an
oval form, with four elastic threads. If I were to put some of this
dust on a glass slide, and look at it under the microscope, I should
see a curious sight. The four threads would be spread out, but if I
were to breathe on the glass, these threads would coil themselves
round the oval body; but as soon as the effect of the moisture had
passed away, the threads would shoot out again in the same position as
they were at first, causing the spore to leap as if it were alive.
The stems are of two kinds, fertile and unfertile; the one you have in
your hands is a fertile spike, and appears only in the spring; the
unfertile ones have no dust-like fruit, and have numerous jointed
branches growing in rows, or whorls as they are termed, round them;
they remain throughout the summer, and in some places form quite a
thick cover. Feel how rough the stem is; this is due to the presence
of a quantity of silex or flint in it; on this account some of the
species are used for polishing purposes. One kind, under the name of
"Dutch rushes," is imported from Holland, being used for polishing
mahogany, ivory, metal, &c. The horse-tails for the most part grow in
moist ground, in ditches and on the borders of lakes; some, however,
are common in corn fields and on the roadside. In this country they do
not attain a height of more than a few feet, but in tropical countries
one or two species grow to the height of sixteen feet or more.
[Illustration: HYDRÆ, ON ROOTS OF DUCKWEED.]
Now for a dip with the bottle in this pond. I will try and catch a few
Hydræ. Strange animals, indeed, they are, and strange is their
history; but let us catch a few first. Nothing yet in my bottle like a
hydra. Ah! now we have one or two. You see a small creature sticking
to the stem of a bit of duckweed; around its mouth are five or six
little projections. At present they are contracted; but the hydra is
able to lengthen them out, when they appear as long, thin lines, which
are used as the creature's fishing-lines; it is not much larger than a
pin's head at present, but it can stretch its body out as it does its
lines. I will take a handful of duckweed, and put it, dripping wet,
into this bag, and when we get home we will place the whole in a glass
vessel full of water. In the course of half an hour or so, we shall,
no doubt, see several hydræ, probably of different species, in various
attitudes--some hanging loosely down, others erecting themselves in
graceful curves and throwing out their arms or tentacles many times
longer than their bodies; others shooting up their arms right above
their heads; others contracted, looking like miniature dabs of jelly;
others attached head and tail to the side of the glass; others
floating on the surface of the water, their tail-ends sticking out and
serving to keep them from sinking; some of a beautiful grass-green
colour, others light brown or flesh colour, others almost white,
others red. These creatures may be cut into several parts, yet each
part will grow again into a perfect animal; young ones bud out of the
sides of the parents. Some have said that they can be turned inside
out, and find no inconvenience whatever from the operation. "But how,"
asked Willy, "could anybody manage to turn so small a thing as a hydra
inside out?" It does seem an impossible task, I confess, and a man
must have much skill and patience to enable him to accomplish it.
However, I will give you the description of an attempt made many years
ago by a celebrated naturalist of Geneva, named Trembley, who made the
hydræ or fresh-water polypes a study for many years. This is what
Trembley says:--"I begin by giving a worm to the polype on which I
wish to make an experiment, and when it is swallowed I begin
operations. It is well not to wait till the worm is much digested. I
put the polype, whose stomach is well filled, in a little water in the
hollow of my left hand; I then press it with a small forceps nearer to
the tail end than to the head. In this way I push the swallowed worm
against the mouth of the polype, which is thus forced to open, and by
again slightly pressing the polype with my forceps I cause the worm
partly to come out from its mouth, and thus draw out with it an equal
part of the end of its stomach. The worm, coming out of the mouth of
the polype, forces it to enlarge itself considerably, especially if it
comes out doubled up. When the polype is in this state, I take it
gently out of the water, without disturbing anything, and place it on
the edge of my hand, which is simply moistened, so that it may not
adhere too closely. I oblige it to contract more and more, and this
also enlarges the stomach and mouth. The worm then is partly coming
out of the mouth, and, keeping it open, I then take in my right hand
a hog's bristle, rather thick and without a point, and I hold it as
one holds a lancet for bleeding. I bring its thickest end to the hind
end of the polype and push it, making it enter into its stomach, which
is the more easily done as in that part it is empty and much enlarged.
I push on the end of the hog's bristle, which continues to invest the
polype. When it reaches the worm, which holds the mouth open, it
either pushes the worm or passes by its side, and at last comes out by
the mouth, the polype being thus completely turned inside out."
[Illustration: HYDRA, WITH YOUNG ONES BUDDING OUT FROM ITS SIDE.]
Very strange, indeed, to think that animals with the wrong side
outermost should continue to eat, grow, and multiply, as Trembley
assures us his specimens did, though, perhaps, we shall not wonder
that they often tried to turn themselves back to their original
condition, and with success, unless Trembley took steps to prevent
them. There are other strange things recorded of the fresh-water
polypes, as that different individuals can be grafted together without
the slightest inconvenience to any of the parties, the joint-stock
company of course being limited.
The hydræ live on small worms, larvæ of gnats, water-fleas, and other
minute creatures; they catch them with their tentacles or
fishing-lines, and draw them to the mouth. It is maintained by many
observers, with good reason, that these arms have the power of
paralysing, in an instant, the worms they wrap themselves round. There
are at least three well-marked species of hydræ to be met with in the
ponds and ditches of this country. There is the green hydra, the
light flesh-coloured or common hydra, and the long-armed hydra, the
most interesting of all. See, there is the water-primrose, now in
flower, with its delicate pink corolla and bright orange centre. Let
us gather a few plants, and then return home.
[Illustration]
FOOTNOTES:
[Footnote B: 'Marvels of Pond Life,' by H. J. Slack, p. 92.]
WALK V.
MAY.
To-day we will go to Shawbury and try our luck with the trout. If the
fish will not rise there will be plenty to observe, and I have no
doubt we shall enjoy the day thoroughly; the wind is in the south-west
and the day is cloudy; the May-fly is well out, and I think we have
every chance of good sport. Let us look out our fishing-tackle and
drive off at once to the river. How delightful it is to stroll by the
river side and hear the rippling of the water; delightful, too, is the
sensation of feeling at the end of your line the tugs and jumps of a
good lively trout. I cannot resist quoting some lines from 'The
Angler's Song,' which I think you will say are very pretty:
Merry in the greenwood is the note of horn and hound,
And dull must be the heart of him that leaps not to their sound;
Merry from the stubble whirrs the partridge on her wing,
And blithely doth the hare from her shady cover spring;
But merrier than horn or hound, or stubble's rapid pride,
Is the sport that we court by the gentle river side.
Our art can tell the insect tribe that every month doth bring,
And with a curious wile we know to mock its gauzy wing;
We know what breeze will bid the trout through the curling waters leap,
And we can surely win him from shallow or from deep;
For every cunning fish can we a cunning bait provide,
In the sport that we court by the gentle river side.
Where may we find the music like the music of the stream?
What diamond like the glances of its ever-changing gleam?
What couch so soft as mossy banks, where through the noontide hours
Our dreamy heads are pillowed on a hundred simple flowers?
While through the crystal stream beneath we mark the fishes glide,
To the sport that we court by the gentle river side?