Chapter II: Part 2

As soon as he spoke, the baby chaffinches stretched out their slender little necks, opened their wide, gaping mouths, and cried for food.

“_Pink, Pink, Pink!_” came from a neighbouring tree.

“Come down, Frank!” Uncle George whispered. “Let us go back from the nest, and we will perhaps see the old birds feeding them.”

With another “_Pink, Pink, Pink_,” the cock chaffinch flew down and stood on the edge of the nest. He had something in his bill. This he dropped into one of the gaping little mouths, and flew away.

Next came the hen bird with something in her bill. She fed another of the hungry little birds, and flew away also.

The boys were greatly interested. They wanted to stay the whole afternoon and watch the chaffinches feeding their young, but their uncle would not allow this.

“No, no, my dear boys,” he said, “we must not annoy our little feathered friends too much, or they may forsake their beautiful nest and their helpless young ones.

“We will come back in a fortnight and see the young birds. You will not know them then, for they will be fully fledged.”

“What do you mean by ‘fully fledged,’ Uncle George?” Tom asked.

“It means covered all over with feathers, does it not?” said Frank.

Their uncle nodded.

“Are these little birds not cold without feathers?” asked Tom.

“Oh, dear, no,” his uncle answered. “During the day they cuddle up together in their cosy nest. At night the mother bird folds her wings over the nest.”

“Where does the cock bird go at night?” asked Tom.

“He sleeps on a branch quite near the nest,” his uncle answered.

“I have just two more questions to ask, Uncle George,” said Frank. “What do the chaffinches feed their young ones on? and what becomes of the young birds after they are fledged?”

“They feed their young chiefly on small worms, flies, grubs, beetles, and other insects. When the young chaffinches are fledged, their parents lead them from the nest. They teach them to fly, and show them where to find their food. They never lose sight of them until they are quite grown up and able to take care of themselves.”

Exercises on Lesson VIII.

1. Describe and compare the nests of rook, thrush, and chaffinch.
Where would you look for each?
2. How does the chaffinch, in building his nest, imitate the colour of
the tree it is built on. Can you see any special reason for
this?
3. Make a list of all the British birds you know. Then divide this
list into—(1) pretty birds; (2) plain birds; (3) singing
birds.
4. Write a description of any bird’s nest you have seen, stating where
and how it was built, and also what you learned from it.

IX.—PLANTS THAT ARM THEMSELVES.

“Some time ago,” said Uncle George, “I promised to tell you something about how plants arm themselves. And here, in this hedgerow, we have some good examples of armed plants.”

“There is the stinging nettle,” said Tom, pointing to a large patch at the roadside.

“The stinging nettle is certainly well protected,” said his uncle. “You have only to touch any part of it lightly with your hand to find that out. Every part of the plant is covered with small needle-shaped hairs. These hairs are hollow and contain a poisonous juice. At the base of each hair there is a bag filled with this juice, while the tip of each is sharp and very brittle.

“When your hand touches a nettle—unless you grasp it tightly—the sharp hair pierces the skin. It’s brittle point breaks off and the poisonous juice is poured out.”

“Why is the nettle covered with these horrid stings?” asked Frank.

“To save it from being eaten up, of course. The nettle is a tender and juicy plant, and, if it were not for its stings it would soon disappear altogether.

“Now, here is another armed plant, the blackberry or bramble. The stem and also the backs of the leaves are covered with large curved prickles. These prickles not only protect the plant from grazing animals, but they help it to climb and scramble up walls and hedges.

“If you try to pull a bramble branch down out of the hawthorn hedge, you will find it rather difficult, for its large prickles are all turned one way. They are really sharp hooks.”

“Here is a wild rose bush. It is also covered with large hooked prickles,” said Frank.

“Yes, Tom, and, like the bramble, it threads its way among stronger and taller plants.

“The wild gooseberry growing close beside it is also armed with prickles. But the prickles of the gooseberry are for protecting its tender leaves. It is not a climbing plant like the rose and bramble. The raspberry also is covered with many sharp little prickles. There is a clump of these plants growing at the other side of the road. Let us cut off a small branch of each of these plants and take them home.”

1. Thistle.
2. Blackberry.
3. Whin.
4. Barberry.
5. Raspberry.
6. Sloe.
7. Buttercup.

“This is the most prickly plant of all,” said Frank, as he halted before a huge thistle. “You can scarcely touch it without getting severely pricked.”

“The thistle is well armed,” said Uncle George. “There are sharp prickles on its leaves, on its stem, and on its flowers.”

As they walked down the road they came upon a mass of whin bushes.

“Here,” said Uncle George, “we have a plant which has turned its leaves into sharp spines.” He bent down and pulled up a tiny plant which was growing under the larger gorse bushes. “Look at this little plant, boys. This is a young whin plant.”

“But it is not a bit like the whin, Uncle George,” said Tom. “Its leaves are soft and flat. They are more like clover leaves. There are no spines or prickles on this little plant.”

“That is so, Tom; but still it is a young whin plant.

“There are a great many of these young whins growing under the older bushes. Let us take a few of them home. If we grow one of them in a pot, and supply it with plenty of water, we will find that it will _never_ produce sharp prickles.”

“That is very wonderful,” said Frank.

“It is,” said Uncle George, “and it teaches us something of the whin’s history. Like the nettle, the whin is a juicy plant, and, if it were not for its prickles, would be eaten by cows, sheep, and horses. In fact, some farmers give whins to their horses. Of course the whins are passed through a mill first. The mill crushes the whins and destroys the prickles.

“It shows us that many, many years ago the whin was a soft-leaved plant like the clover. It grew in moist soil. But by and by other plants invaded the land. These plants grew more quickly than the whin, and choked it out of the rich moist soil. Forced to grow upon bare hill-sides and commons, the soft-leaved juicy whin would be destroyed by grazing animals if it did not arm itself with sharp spines.

“Here is the blackthorn or sloe. It bears many hard, sharp-pointed spines. Yet, if we grow a sloe plant in the garden, we find that its sharp spines gradually disappear. They become branches bearing leaves and flowers.

“But plants have other ways of protecting themselves against animals. Look through the hedge into the meadow and you will notice that while the grass has been eaten bare, there are other plants which have been left to grow up untouched. Buttercups grow up all over the field, and tall ragwort plants. How is it that the cows do not eat these plants? They are not armed with spines or prickles.

“They protect themselves in another way. They contain bitter or poisonous juices. No cow will eat a buttercup. If it did so it would be ill and uncomfortable for a time.

“I want you to notice, boys, that—with the exception of those plants, like the bramble and wild rose, which use their prickles for climbing as well as for protection—all our armed plants grow in exposed places. The thistle and whin are good examples of this.”

Exercises on Lesson IX.

1. Take in twigs of hawthorn, barberry, holly, bramble, and
gooseberry. Examine, and sketch them so as to show their
protective parts.
2. Grow a small whin bush in a pot and water it daily. Note that the
_new growth_ it makes is tender, and that _no spines_ are
produced.
3. Some plants are covered with dense woolly hairs. These are seldom
eaten by cattle. Can you explain why?
4. Make a list of all the armed plants you know, and tell how each is
protected.

X.—THE HORSE POND AGAIN.

Frank and Tom returned from the horse pond one day with their jars filled with curious creatures.

“We took the water beetle back to the pond, Uncle George,” said Frank, “and I almost felt sorry to let such a cruel and greedy monster loose among the other creatures in the pond.”

“You have here creatures even more cruel and greedy than the diving beetle,” said his uncle, looking into the glass jars which the boys had brought.

“Here is the larva of the diving beetle, and a fiercer or greedier creature is not to be found in the whole world.”

Uncle George refilled the three large tanks. He poured the contents of one of the jars into one of the tanks. It contained, besides the larvæ he spoke of, a number of tadpoles, some small stickle-backs, and a great many water snails or whelks.

In addition to these, there were one or two curious insects, with a pair of very long legs. They came to the surface every now and then, and moved their long limbs like oars. Whenever the tank was touched, they would suddenly dive to the bottom. Here they would remain for a short time, then, returning to the surface, would “oar” themselves along as usual.

“What are these queer things, Uncle George?” Tom asked. “They look exactly like little boats.”

“They are beetles,” Uncle George replied, “and they do resemble little row-boats—so much so that they are called ‘water boatmen.’ This beetle’s body is shaped like a boat, and he lies on his back and moves his very long hind legs exactly like oars. He has a large, sharp beak, which you can see if you look closely.”

Just as Uncle George was speaking, a small fly alighted on the surface of the water. It was immediately seized by a water boatman, who dived with it to the bottom of the tank.

1. Water Boatman.
2. Water Whelk.
3. Water Hog Louse.

“That is how the creature feeds,” said Uncle George. “When an unlucky fly comes near, he seizes it with his two fore pairs of short legs, drives his cruel beak deep into its body, and dives with it to the bottom of the pool. When he has drowned his victim, he devours it at leisure.

“But let us look at the creature I first spoke of—the larva of the diving beetle.”

There were several in the tank. Uncle George lifted one out with a small gauze net. He placed it in a saucer of water and asked the boys to sketch it.

“It has six legs,” said Frank. “Its head is large and flat, and there are two things like horns sticking out of it.”

“These are the creature’s jaws,” said his uncle.

Uncle George touched the creature’s head with the point of his pencil. Instantly the long, curved fangs moved apart, and the creature sprang at the pencil and closed its fangs upon the wood.

1. Larva of Diving Beetle.
2, 3. Head, showing how Fangs work.
4. Larva seizing Tadpole.

“What a fierce creature,” said Tom.

“Yes,” replied his uncle. “We must remove the others from the tank, or there will be nothing left alive in it. See, one of them has caught a tadpole already.” And, sure enough, the creature had sunk his cruel pincers deep into the body of a tadpole. He shook the tadpole as a dog would shake a rat.

“Those huge fangs are hollow,” Uncle George continued. “With them he sucks every drop of blood from his victim’s body. In this way he devours tadpoles, whelks, little fishes, and even his own weaker brethren.

“We shall have to put these larvæ in a tank by themselves, and feed them upon pieces of fresh raw meat, to keep them from devouring one another.

“Now, boys, I am going to describe this larva. Look closely, and see if I am right. You can correct your drawings as we go along.

“His body, which is nearly two inches long, is narrow at each end and broad at the middle. It is divided into twelve segments, and to each of the first three of these segments a pair of legs are attached. His large, flat head is almost heart-shaped. At its broad end are a pair of large, beady eyes, three pairs of organs which look like feelers, and the two large, curved fangs with which he seizes his prey.

“Notice how beautifully the legs are adapted for swimming. They are edged with long, stiff hairs, which stand out flat with every down stroke, but fold in when the legs move upwards. That is how the creature is such a graceful swimmer.

“The last three segments of his body are thickly covered with long hairs. His tail is divided into two long plumes. You can see what these are for, I hope.”

“Oh yes,” said Frank. “Like the parent beetle, the larva comes often to the surface and hangs downwards with his tail exposed to the air. So these plumes must be his breathing organs.”

“And do these long, slender creatures actually become broad, stout beetles like the one we returned to the pond to-day?” Tom asked.

“Yes, Tom, they do. Just as your green caterpillar became a beautiful white butterfly. These larvæ hatched out of eggs which were laid by the female beetle in the stem of some water weed. She first cuts a slit in the water weed, and then places an egg in the slit.

“When the larvæ are full grown, they crawl out of the pond and bury themselves in ground. Here they pass the winter in the pupa stage. They come out in spring, fully-formed beetles, and pass the remainder of their lives in the water.”

“What are these curious creatures that crawl among the water weeds?” Frank asked. “They are very like the ‘slaters’ which we find among old wood-work in the garden.”

“That creature is the ‘water hog.’ Its proper name is _Asellus_, and it is very closely related to the garden ‘slater’ or wood-louse.

“These water hogs, like the whelks, are very useful in an aquarium. They eat up all waste matter, and so help greatly to keep the water fresh.

“By the by, I want you to watch the whelks from day to day. They usually lay their eggs in a clear, broad band on the inside of the glass tank; and with our lenses we can watch the changes in these eggs nicely.”

Exercises on Lesson X.

1. Procure some “water boatmen” from the nearest pond (see Appendix),
feed them upon flies, and watch their habits. Notice
particularly their method of swimming and of feeding.
2. We should not keep all our pond animals in one tank. Can you
explain (giving examples) why this is?
3. Write the life-history of the diving beetle.
4. Make large sketches of the diving beetle and its larva. Compare
them.

Water Beetles.
Hog Lice.
Water Whelks.
Water Boatman.

XI.—WASPS.

The wasp’s nest was found at the edge of the wood, hanging from the branch of a small tree. It was greyish white in colour, shaped like a pear, and about the size of a hen’s egg.

Queen Wasp.
Worker Wasp.
Queen Bee.
Worker Bee.

Uncle George removed it from the branch and carried it home carefully, for it was very light and very fragile. He took a pair of scissors and cut through the thin walls so as to remove nearly half of the coverings. When he had finished cutting, two thin, papery shells fell upon the table, one a size smaller than the other.

“Examine the stuff the wasp’s nest is made of, and tell me what it is most like, boys,” he said.

“It is more like paper than anything else,” said Tom.

“It _is_ paper,” said his uncle.

“Where did the wasps find this paper?” Frank asked.

“Not ‘_wasps_,’ Frank, but _wasp_,” his uncle answered, “for this nest was all built by _one_ wasp. The insect did not find the paper. She made it. It was the wasp who first taught man to make paper.

“The queen wasp awakens from her winter sleep in spring, and at once sets about making her nest. She gathers tiny fragments of wood and bark, chews them up, and mixes them with a fluid from her mouth. This, when it hardens, is paper.

“First she makes a stiff rod, or pillar, of paper. This hangs down from the branch and forms the centre of the nest. Round this are built the walls of her house.

“Observe, boys, that there are two distinct walls of paper, one inside the other; and there is a wide air space between them all the way round. The entrance to the nest is at the bottom. Round the centre pillar there is a little thing shaped like an opened umbrella. If you look underneath this, you will see something curious, I think.”

“Oh,” said Frank, “it is divided into six cells, and in each cell there is a small, stout maggot or grub. I can see them moving.”

“These are the young wasps,” said Uncle George. “Like your butterflies and caddis flies, the wasp passes through egg, larva (or caterpillar), and pupa stage before it becomes a perfect insect. These are in the larva stage but, unlike your caterpillars, they have no legs, and they cannot feed themselves.”

“Then the mother wasp must have laid an egg in each cell,” said Frank, “and these grubs hatched out of them.”

“That is so,” said Uncle George. “You see what a clever and industrious creature a wasp is. To build this beautiful nest all alone and unaided, and to rear and feed her helpless grubs, is a task indeed.”

“What are the wasp grubs fed on?” asked Frank.

“At first,” said Uncle George, “they are fed on animal food, and this keeps the queen wasp hunting insects all day long. As they grow older, they are fed upon honey.

Nest of Wasp in Spring.
A. Outer wall.
B. Inner wall.
C. Air space.
D. Cells with larvæ.
Same Nest in Autumn.
A. Combs of cells.
B. Supporting pillars.
C. Entrance.
DD. Inner and Outer walls.
E. Air space.

“The wasps which come from these first eggs are ‘worker’ wasps. As soon as they are hatched out, they begin to enlarge the nest. This they do by removing the inside wall and building a new and larger outer wall. This is done from time to time, until at last the nest becomes as big as an ordinary-sized turnip. While this is going on, more and more cells are being built inside, until at last five or six large combs of cells fill the inside of the nest. The queen wasp lays an egg in each cell as it is formed; and the worker wasps gather food and nurse the young grubs until they become perfect wasps.

“By and by some young queens, or female wasps, are hatched out. These lay eggs, and soon the population the paper nest numbers many thousands.”

“And that is why the gardener kills every wasp he sees in spring time,” said Frank.

“Every wasp we see in spring,” said Uncle George, “is a queen wasp. If allowed to live, each queen would become the founder of a nest and the mother of thousands of wasps.”

“But why destroy the wasps?” asked Tom.

“Because wasps are very destructive and dangerous insects,” said Uncle George. “They destroy our best fruit, and their sting is poisonous, sometimes causing death.”

During the summer the boys found several wasp’s nests. One was built under-ground at the roadside. Another was built inside a wren’s nest. The queen wasp who built it had driven the wrens out. A third nest hung from the branch of a gooseberry bush in the garden.

The latter was watched by Uncle George and the boys as it grew larger and larger. Soon, however, the wasps became too numerous. One day they chased Tom and Frank out of the garden and stung them badly. Then Uncle George removed the nest. Putting on his bee-veil and gloves, he cut off the branch from which the nest hung. He put nest and branch inside a large box; and, having placed a saucer containing burning sulphur inside the box, he closed the lid.

In the morning the wasps were all dead, and the boys examined the huge nest. Thus they were able to see queens, workers, and male wasps, eggs, larvæ, and pupæ, and to make drawings of each.

“What becomes of the wasps in winter?” Frank asked his uncle.

“They come to a sad end, Frank,” said Uncle George. “They do not store food like the hive bee, and so, when the cold weather comes, they starve to death.

Queen Humble Bee.
Worker Humble Bee.

“Our good-humoured and hard-working friend, the humble bee, shares the same fate. A few young queens leave the nest before winter comes on. These bury themselves in mossy banks and sleep the winter through.”

Exercises on Lesson XI.

1. Look under low branches of larch and spruce trees in spring for the
nest of the wasp. Make a drawing of it. Cut it open and
examine the interior.
2. Compare a piece of the wall of the nest with the torn edge of (1) a
piece of coarse brown paper and (2) a piece of ordinary
newspaper.
3. Write out the life-history of a wasp.
4. Compare the combs of the hive bee with those of the wasp. Notice
that the former are placed vertically in the nest, the latter
horizontally. Observe how the wasp’s combs are kept apart.

XII.—THE DANDELION.

Uncle George and the boys were having a stroll along a lane where briar and hawthorn and all sorts of wild flowers grew. Although it was an October day the sun was shining brightly, and all along the wayside the golden flowers of the dandelion opened wide to the sunlight.

“I thought that the dandelion was an early summer flower,” said Frank.

“So it is,” said his uncle; “but this year the autumn has been so warm that our dandelions are flowering a second time. This often happens with many of our wild flowers during an extra mild season.

“You ought to dig up one of these dandelion plants, take it home and grow it in a pot. It is a most interesting plant to observe, especially the growth and ripening of its seeds. I see here dandelion flowers in almost every stage of their growth.

“If you look you will find among the wide open flower-heads many others which are closed. Let us split a few of these down the centre, and we will find that they are not all alike.

“Here is one with a bright yellow tip. This one has not yet opened. If you use your lens you will notice that, like the daisy, this is not a single flower, but is made up of a great many small yellow florets. These florets stand upon a flat round disc, and they are surrounded by two rings of green things called bracts. One set of these bracts stands up straight. These protect the florets. They open and close the flower. The down pointing bracts protect the flower from ants and crawling insects.

“Now, Frank, look at the split flower and tell me what you see with your glass.”

“The florets are all of one kind,” said Frank. “They are all strap shaped, and there are a great many of them. The younger florets are in the middle.”

“If you were to pull the florets out and count them you would find about three hundred of them in a single flower-head,” said Uncle George.

1. Dandelion Flower-head not yet opened.
2. Single Floret of same.
3, 4, 5. Flower-head closed for Seed ripening.
6. Second time of opening.

“Now, take one single floret and examine it, please. It is very like the outer (white) florets of the daisy. But it is more complete. There is a large seed-vessel at the bottom. Just above this there are a great number of long silky hairs. You will see what these are for by and by. The lower part of the floret is tubular, but it opens up into a long yellow strap-shaped petal. There are really five petals all joined together here.”

“Oh yes,” said Frank, “at the top of the floret I can see five distinct teeth, and five ridges run down from them. I also see the barrel-shaped ring of stamens.”

“Let us gather some more of the closed flowers,” said Uncle George.

“Here are two other closed flowers. One of them has a yellow tip, withered and faded almost to brown. The other has a white woolly tip.”

“Have these not opened yet?” Tom asked.

“Oh yes! they have opened and closed up again. The dandelion opens out to the sun so that flying insects may visit it and carry pollen from flower to flower. When it has received, in this way, enough pollen to enable its seeds to form, it closes up completely and remains closed until its seeds are ripened. During this time the short stalk between the seed-vessel and petal part grows long. If you look again at a single floret you will see that this short stout stack bears the long straight hairs I spoke of. The flower-head closes so tightly that the yellow strap-shaped petal parts of the florets are squeezed together into a bunch. They soon wither. Meantime all the hair-tipped seed-stalks are growing longer and longer. At last they push the bunch of withered petals right out of the flower and it falls off.”

Uncle George then gathered a few more closed heads, and, by cutting them open, showed the boys all the stages in the growth of the seeds.

“When the dandelion flower-head opens for the last time, instead of a flat golden mass of florets, this is what appears.” As he spoke, Uncle George pointed to a dandelion head which was one huge fluffy ball of stalked seeds.

Frank held it up and blew his breath upon it. Immediately all the seeds went sailing through the air.

“Why does the flower-head keep closed when the seeds are ripening?” asked Tom.

“Because,” answered Uncle George, “not only has the seed to ripen, but a plumed stalk has to be formed by means of which the seed is carried away from the parent plant. These plumes have to be perfectly dry or they would be of no use as sails to the seed. Notice that it is only on dry days that these ‘clocks’ of the dandelion appear.”

“But, Uncle George,” said Frank, “are these seeds actually fitted with feathery tops so that they may be carried far away from the parent plant?”

“Certainly, my boy. You would not have them all trying to grow in the place where the parent plant grows, would you? There would be no room for three hundred seeds to grow there. Besides that, the parent plant has already exhausted the soil. It is necessary that they should seek pastures new, and therefore the seeds of most plants are furnished with some means of travelling.”

“Are all seeds carried by the wind?” Tom asked.

“Oh dear no,” Uncle George replied, “plants have many ways of scattering their seeds. Some plants, by suddenly bursting their seed-vessels, shoot their seeds far out; some seeds are furnished with little hooks which grip on to the fur of passing animals; some are carried by birds; but by far the greater number are scattered by the wind.

“We shall learn more about these at some future time. Meantime we will grow a dandelion plant at home, and watch the opening and closing of its flowers, and the wonderful way in which its travelling seeds are produced.”

Exercises on Lesson XII.

1. Gather dandelion flowers at different stages of growth. Draw, on a
large scale, a single floret from each,
2. Draw a leaf of the dandelion. Compare it with a primrose leaf. See
if you can make out, from the shape of the leaf, why the plant
is called “dandelion” (_dent de lion_ = “lion’s tooth”).
3. Take in a dandelion plant bearing young flowers. Keep the root in
well-watered soil, or in water only, and watch the growth of
its flowers.
4. Make a list of all the wind-carried seeds you know, and give a
drawing or short description of each.

XIII.—TROUT.

One day in November the postman brought Uncle George a small wooden box. There were holes bored in the sides and top of it. The box, when opened, seemed to be filled with damp moss; but when some of this moss was removed there was found in the middle of the box a piece of folded muslin.

Hatching Bottle.
A. Supply pipe.
B. Exhaust pipe.
C. Trout Eggs.
Rearing Box.
C. Perforated zinc tray to fit box.

Uncle George laid the muslin on the table, and opened it out. It contained a number of tiny pink balls, much smaller than peas.

“These are the trout eggs you promised to get for us, are they not?” said Frank.

“They are,” said Uncle George, “and we must put them into running water at once. I have a bottle here ready for them.”

Uncle George filled a wide-mouthed bottle with water from the tap and placed the eggs in it. He then corked it with a cork in which he had bored two holes.

Into each of the holes he had fitted a tube. One tube was long enough to reach almost to the bottom of the bottle. The other was bent over the outside of the bottle.

The straight tube was connected with the water tap by a piece of indiarubber tubing. He then turned the tap on gently, so that the water went in by the straight tube and came dripping out by the bent tube.

“Trout require a constant supply of fresh water,” he said. “Their eggs are usually laid in shallow streams.

“Now, boys, I want you to watch these eggs and note down any changes you see in them. You can remove the bottle from the tap at any time, but you must not keep it more than fifteen minutes at a time, or your trout will not hatch.”

At the end of a week the boys noticed two black dots and a coiled white line in each egg.

In two weeks more some curious-looking creatures were seen wriggling about among the eggs. As there were some empty egg-skins to be seen, they guessed that these lively creatures must be young trout.

They were not a bit like fish. Each seemed to be made up of a long white streak, which looked like the “backbone” of a fish, a big, clumsy yellow bag with red veins running through it, and two large black spots that looked like eyes.

In a few days all the eggs hatched out, and in place of the little pink eggs there was a crowd of these wriggling creatures and a number of empty egg-skins. The boys were puzzled, and Uncle George had to be consulted.

“I don’t think these were trout eggs,” said Frank. “The creatures that came out of them are not a bit like fishes. They swim on their sides and have a huge yellow bag attached to their bodies.”

“They _are_ young trout, I can assure you, Frank,” said his uncle laughing. “If you remember, your tadpoles were not a bit like frogs when they hatched out of the egg. These huge bags you talk of are called ‘yolks.’ Each trout when hatched is furnished with a huge yolk or food supply.

“The tadpole, when hatched, has also got a yolk upon which he lives without eating for four or five days. Our trout will require no food for six weeks. During that time the yolk will become smaller and smaller, and at last disappear entirely. While the yolk is shrinking, you will notice that the creature gradually assumes the form of a fish.”

Uncle George emptied the bottle containing the young trout into a wooden box which he had made. This box was fifteen inches long, four inches broad, and four inches deep. The inside of it he had charred with a red-hot iron after it was put together. It was placed under the tap, and the water dripped into it all day and all night.

Frank made a small gauze net about the size of a dessert-spoon, and with this they lifted troutlets out of the box whenever they wanted to examine them.

As their uncle had said, the creatures changed from day to day. By placing a single trout in a white saucer, the boys could note these changes; but they were such lively little creatures that making good sketches of them was somewhat difficult.

First the big black dots became more like eyes. Then delicate fins and tail appeared, and mouths which opened and shut. At the top of the yolk-sac, just under the head, the boys could see a little red thing like a heart beating constantly. As the yolk-sac grew smaller, the little fish’s body grew more shapely, and tiny brown spots appeared all over it.

At last, at the end of six weeks, the yolk was completely gone, and the young trout were now beautiful little fish, shaped and coloured exactly like big trout.

Then Uncle George began to feed them. They were fed four times a day on the yolk of an egg which had been boiled for half an hour. A very small quantity of this hard yolk was squeezed through a piece of gauze into the water, and the little fishes dashed at it and gobbled it up greedily.

They were so rapid in their movements, swimming about and leaping out of the water, that the boys were never tired of watching them.

“What are the brown spots on a trout for?” Frank asked his uncle one day.

“The trout is protected by his colour,” said Uncle George. “Each trout is coloured like the bed of the stream he lives in, and the spots resemble grains of sand and tiny pebbles. The trout can change his colour, like the frog, as I will show you.”

Uncle George took two trout out of the box and placed them in a glass dish. He placed the dish in a white saucer, and so arranged it that water was kept flowing into and out of it.

Next day he took two more trout out of the box and placed them in the glass dish. It was then seen that the first two trout had grown quite light in colour. They were much paler than those taken out of the box, the inside of which was charred and black.

One day Uncle George found two of the trout dead in the box.

“I am afraid, boys,” he said, “that we cannot keep them confined any longer. Get a large pail full of water, and we will carry them to the brook.”

“We must come here and fish next year, Frank,” said Tom, after the trout were transferred to the brook. “How long will it be before they become big trout, Uncle George?”

“They are now about an inch long,” said Uncle George. “In a year they will be four inches long. In about three years, if they are not devoured by larger trout, they will weigh about a pound apiece.”

“I think it is a shame to kill such pretty little creatures,” said Frank.

“I quite agree with you, Frank,” said his uncle.

Exercises on Lesson XIII.

1. Compare a newly-hatched trout with a seed (bean). How do they
resemble, and how do they differ from one another?
2. The trout is protected by its colour markings. Make a list of any
other animals you know that are “colour protected.”
3. If you put a fish (trout) into water which has been boiled and
allowed to cool, it dies. What are your reasons for this?
4. Make notes, with sketches, of the development of a young trout from
the time it is hatched until it requires food.

XIV.—SILKWORMS.

The silkworm eggs came in a very small box. They were sent by a friend of Uncle George’s who lived in the south of England. The eggs were stuck to pieces of paper in scattered groups. Some pieces of paper had only one or two eggs on them, others had as many as forty. They were small, round things, flattened on the top, and coloured light green. They reminded the boys of small mustard seeds, but they were not so round.

In answer to Frank’s question as to why the eggs were laid in irregular groups, Uncle George answered:

“When the silk-moth emerges from her pupa case, she lays her eggs anywhere on the floor of her cage. As the eggs are coated with a gluey material when newly laid, they stick firmly to the floor.

“Those people who rear silkworms always have a sheet of clean paper covering the floor of the cage before egg-laying commences. After the eggs are laid, they are found adhering to this sheet of paper. The paper is taken out of the larva cage, and those parts containing eggs are cut out with scissors.”

“How many eggs are laid by one moth,” Frank asked.

“From four to five hundred,” his uncle replied. “Let us get our larva cage cleaned out, and we will put these eggs in the lower part of it and await their hatching.”

“Why in the _lower_ part,” Frank asked, as he set about cleaning the cage.

“Because its floor is a drawer which can be pulled out. If you put them in the upper part, you must lay a sheet of paper on the floor first, for your silkworms must not be handled on any account.”

“And how long do we have to wait for these eggs to hatch?” asked Tom.

“That depends altogether upon the amount of warmth they receive, Tom. They will remain unhatched ever so long if kept in a cool place; but whenever they are placed where they can get the necessary amount of warmth, they begin to hatch. Let us put them in the front window, where they can get most sunshine.”

About a week after the larva cage was placed in the window, Frank reported to his uncle that some of the eggs had turned white.

“Take your lens and examine carefully those eggs which have lost their colour,” said Uncle George.

Lifting out one of the small pieces of paper with eggs on it, Frank examined it with the glass.

“Oh,” he said, “these colourless eggs are just empty shells, and there are two small creatures crawling along the edge of the paper. How small they are! They are no longer than the breadth of a pin-head. They are almost black in colour, covered all over with hair, and have very large heads.”

“Well, these are newly-hatched silkworms,” said Uncle George, “and they are already looking for food. Run out to the garden and bring in some fresh lettuce leaves.”

Uncle George carefully dried the lettuce leaves before putting them into the cage. In two days all the eggs were hatched, and in their place were as many black, hairy, crawling little creatures with clumsy heads. Although they did not seem to eat much, they grew very rapidly. When three days old, they were fully twice as big as when hatched.

In five days the silkworms seemed to have increased in number as well as in size. In fact, there seemed to be twice as many grubs as there were of eggs.

Then Uncle George explained that half of these were not grubs, but simply empty skins.

“The silkworm, in order to grow, must cast its skin,” he said. “It does this four times during its lifetime. Look out for another _moult_, or skin-casting, in four days’ time.”

Four days later the grubs cast their skins again, just as Uncle George had said. They were now about half an inch in length, and much lighter in colour.

In six further days they moulted a third time. Instead of dingy, hairy grubs, they were now hairless caterpillars, yellowish-white in colour, and with round black heads. Their fourth and last moult took place in another week. By this time they were over an inch in length. They now began to eat the lettuce leaves ravenously, and grew very fast. For ten days they ate much and grew rapidly. Then they seemed to get tired of feeding, and began to crawl lazily up the sides of their cage.

1. Eggs.
2. Larva.
3. Silk Cocoon.
4. Chrysalis.

“They are full grown now, boys,” said Uncle George, “and will soon begin to spin their silken cocoons.

“They are now about three inches long, and very different from the tiny hairy grubs which came out of the eggs over a month ago.”

“We have been comparing drawings of them with drawings we made of the caterpillar of the white cabbage butterfly,” said Frank, “and we find that they are very much alike.”

“That is good,” said Uncle George. “They are, indeed, very much alike. The body is made up of thirteen segments, and they have the same number of legs. They differ from the cabbage caterpillar, however, in size and colour. Notice the little horn which sticks up out of the twelfth segment. Your cabbage caterpillar did not have that. If you look closely you will notice a long silk thread issuing from the head of one of these silk-spinning caterpillars. This one has just begun to make his cocoon; and, in order to prevent his threads becoming entangled with those of the other caterpillars, I will place this small paper cone over him.”

Next day Uncle George covered several of the caterpillars with paper cones. On the roof of the cage the boys saw one caterpillar surrounded with a flimsy web of silk of a golden-yellow colour. As they watched the creature turning its head round and round inside the silky veil, their uncle told them that the creature was spinning silk at the rate of about a foot per minute.

In three days each caterpillar had surrounded itself with a dense silken cocoon as large as a walnut. Then Uncle George took one of the cocoons, and, cutting it open, showed the boys the brown, shining chrysalis inside. He took another cocoon, and, having dipped it into warm water, began to wind the silken thread on to a piece of card.

Both Frank and Tom were amazed at the length of this silken thread. They were more surprised when they were told that each caterpillar produces a silk thread more than half a mile long.

“Tell us, please, Uncle George,” said Frank, “why the creature spins all this silk, and how it makes it?”

“You are asking a difficult question,” said his uncle, “but I will tell you something about it.

S. Silk Fibres.
W. Wool.
C. Cotton.
(All highly magnified.)

“The creature spins this cocoon to protect its chrysalis, of course. The silk is produced in two long, coiled tubes, which occupy nearly the whole length of the creature’s body.

“Silk, before it issues from the caterpillar’s body, is a fluid. Whenever it comes out into the air, it becomes horny. Two strands are produced at once—one from each of the long coiled tubes. Before they leave the caterpillar’s body they are pressed together to form one flat, ribbon-like thread. Silk is one of the strongest fibres in the world. It is nearly as strong as steel, and much stronger than many of our metals.

“In a fortnight your silken cocoons will produce white, fluffy moths. ‘Then you can supply your friends with hundreds of ‘silkworm’ eggs, and still have enough over to stock your larva cage.”

Exercises on Lesson XIV.

1. Are “silkworms” really worms? What creatures do they most resemble?
2. Many of our common caterpillars spin silk of a kind. Take in
“woolly bear” caterpillars. Feed them on the plants you find
them on. Compare the cocoons they make with those of the
“silkworm.”
3. Compare egg, larva, pupa, and perfect insect of the “silkworm” with
that of the white cabbage butterfly. Does the caterpillar of
the latter spin any silk?
4. Make a list of all the spinning insects you know, and try to
explain the use of the “silk” thread in each case.

APPENDIX.
HINTS TO TEACHERS.

STRUCTURE OF STEMS.—One- and two-year-old twigs of horse-chestnut, elm, and willow should be cut into half-inch lengths and distributed among the class. If cut straight across with a sharp pen-knife, the different layers can be seen with the naked eye. Afterwards these pieces should be slit longitudinally, and the various tissues _peeled off_ by the pupils.

BULBS AND CORMS.—Bulbs of snowdrop and tulip, and corms of crocus, can be bought from seedsmen, from September to January, at from 6d. to 1s. per 100. At any other season of the year the onion will make a good substitute.

WILLOW TWIGS will root readily if placed in water and kept near the hot pipes in school.

VEGETABLE FINGERS.—To illustrate this lesson, peas (of any kind) ought to be grown in school. Branches of the many wild peas and vetches are to be found in abundance in every hedgerow during spring, summer, and autumn. Branches of Virginia creeper, clematis, tropæolum (Indian cress) may be shown with advantage. The compound leaves of the rose, ash, or mountain ash should be shown along with those of sweet-pea and edible pea, and the amount of green (assimilating) area compared.

THE GREAT WATER BEETLE is found in nearly every pond. One or two should be kept and fed upon small worms. These beetles can also be obtained from any naturalist dealer. The larvæ of this beetle is found in ponds in summer months.

“WATER BOATMAN” BEETLES (_notonecta_ and _corrixa_) are common to all our ponds.

PLANT ARMOUR.—Branches of whin, bramble, hawthorn, and barberry, and leaves of holly, thistle, and nettle will be found to illustrate this lesson. Young whin plants are to be found plentifully in spring, growing under the old bushes. One of these should be grown in a pot in school and kept well watered. It will produce _no_ prickles.

TROUT EGGS are obtainable from any of the fisheries—_e.g._, Howietoun Fisheries, Stirling, or Solway Fisheries, Dumfries, at about 1s. per 100, from October till April. They are easily hatched and reared wherever running water can be obtained. If not hatched in a bottle, as described in Lesson XIII., the ova ought to be placed in a shallow trough of perforated zinc suspended in a small wooden box. The inside of the box must be charred with a red-hot iron to prevent fungal growths. When the yolk-sac is completely absorbed, the young trout should be fed on yolk of hard-boiled egg, and, later on, on a mixture of this and chopped raw beef. In each case the food should be squeezed through perforated zinc.

“SILKWORMS.”—Eggs of the silk-bearing moth (_Bombex Mori_) can be had from Messrs Watkins & Doncaster, 36 Strand, London, and other dealers, at 4d. and 6d. per 100. The larva should be fed on mulberry or lettuce leaves, and the leaves should never be given _wet_.

Caterpillars of Tiger Moth (_Arctia caja_), Emperor Moth (_Saturnia carpini_), or Puss Moth (_Cerura vinula_) should be kept for comparison.

Footnotes

[1]See Book III. Lesson 3.

[2]_Dyticus Marginalis._

PRINTED IN GREAT BRITAIN BY THOMAS NELSON AND SONS, LTD.

The following List gives a rough idea of the main Contents in each Volume of this Series:—

Vol. I. Jack Frost, Woods and Fields in Spring, Holly and Fir, The
Rook, Chicks, Hedgehog, Beetle, Humble Bee.
Vol. II. Sowing the Seed, Life of a Plant, A Country Walk, Harvest
Time, Gulls, Squirrels, Air, Fire, Dew, Rain, etc.
Vol. III. Birds—Seed Eaters and Insect Eaters, A Baby Plant, Uncle
George’s Tank, Tadpoles, Frogs.
Vol. IV. Snowdrop, Crocus, Tulip, Daisies, Water-beetle, Life of a
Trout, Silkworms, Chaffinch, Song Thrush.
Vol. V. Some British Forest Trees—Oak, Ash, Horse-chestnut, Elm,
Birch, Willow, Beech, The Fir Tribe.
Vol. VI. Bats, Field-mice, The Water-vole, Mole, Weasel, Reptiles,
Newts, Stickle-backs, Crayfish, etc.
Vol. VII. Butterflies and Moths, and how to collect them,
Caterpillars, Beetles, Flies, etc.

Transcriber’s Notes

--Retained publication information from the printed exemplar (this eBook
is in the public domain in the country of publication.)

--Only in the text versions, delimited italicized text with
_underscores_.

--Silently corrected several typos.