Chapter XLI: Part III: Plant Life (11)

6. Hunt among the moss for some stems that have pretty, yellowish, starlike cups at their tips. How does the inside of one of these cups look? Ask the teacher to tell you what grows in this cup. Look down the stem and see if you can find last year’s cup. The cup of two years ago? Measured by these cups how old do you think this moss stem is?

7. Select some stems of moss, both those that bear the fruit and those that bear the cups. After they are dried describe how the leaves look. Examine the plant with a lens and note how these leaves are folded and twisted. Do the leaves stand out from the stem or lie close to it? Is this action of the leaves of any use to the plant in keeping the water from evaporating? How do the star-cups look when dry?

8. Place these dried stems in a glass of water and describe what happens to the cup. Examine some of the dried moss and the wet moss with a lens, and describe the difference. Of what use to the moss is this power of changing form when damp?

_Reference_--First Lessons in Plant Life, Atkinson.

MUSHROOMS AND OTHER FUNGI

_Teacher’s Story_

There is something uncanny about plants which have no green parts; they seem like people without blood. It is, therefore, no wonder that many superstitions cluster about toadstools. In times of old, not only did the toads sit on them, but fairies danced upon them and used them for umbrellas. The poisonous qualities of some species made them also a natural ingredient of the witch’s cauldron. But science, in these days, brings revelations concerning these mysterious plants which are far more wonderful than the web which superstition wove about them in days of yore.

When we find plants with no green parts which grow and thrive, though unable to manufacture their own organic food through the alchemy of chlorophyl, sunlight and air, we may safely infer that in one way or another they gain the products of this alchemy at second hand. Such plants are either parasites or saprophytes; if parasites, they steal the food from the cells of living plants; if saprophytes, they live on such of this food material as remains in dead wood, withered leaves, or soils enriched by their remains.

Thus, we find mushrooms and other fungus fruiting bodies, pallid, brown-olive, yellow or red in color, but with no signs of the living green of other plants; and this fact reveals their history. Some of them are parasites, as certain species of bracket fungi which are the deadly enemies of living trees; but most of the fungus species that we ordinarily see are saprophytes, and live on dead vegetation. Fungi, as a whole, are a great boon to the world. Without them our forests would be choked out with dead wood. Decay is simply the process by which fungi and other organisms break down dead material, so that the major part of it returns to the air in gaseous form, and the remainder, now mostly humus, mingles with the soil.

As a table delicacy, mushrooms are highly prized. A very large number of species are edible. But every year the newspapers report deaths resulting from eating the poisonous kinds--the price of an ignorance which comes from a lack of the powers of observation developed in nature-study. It would be very unwise for any teacher to give rules to guide her pupils in separating edible from poisonous mushrooms, since the most careful directions may be disregarded or misunderstood. She should emphasize the danger incurred by mistaking a poisonous for an edible species. One small button of the deadly kind, if eaten, may cause death. A few warning rules may be given, which if firmly impressed on the pupils, may result in saving human life.

Photo by G. F. Atkinson.]

First and most important, avoid all mushrooms that are covered with scales, or that have the base of the stem included in a sac, for two of the poisonous species, often mistaken for the common edible mushroom, have these distinguishing characters. Care should be taken that every specimen be collected in a way to show the base of the stem, since in some poisonous species this sac is hidden beneath the soil.

Second, avoid the young, or button, stages, since they are similar in appearance in species that are edible and in those that are poisonous.

Third, avoid those that have milky juices; unless the juices are reddish in color, the mushrooms should not be eaten.

Fourth, avoid those with shiny, thin, or brightly colored caps, and those with whitish or clay-colored spores.

Fifth, no mushroom or puffball should be eaten after its meat has begun to turn brown or has become infested with fly larvæ.

HOW MUSHROOMS LOOK AND HOW THEY LIVE

There are many kinds of mushrooms varying greatly in form, color and size, but wherever they appear it means that sometime previous the mushroom spores have been planted there. There they threw out threads which have penetrated the food substance and gained a successful growth, which finally resulted in sending up into the world the fruiting organs. In general shape these consist of a stem with a cap upon it, making it usually somewhat umbrella-shaped. Attached to the cap, and usually under it, are plate-like growths called gills, or a fleshy surface which is full of pores. In the case of the gills, each side of each plate develops spores. These, as fine as dust, are capable of producing other mushrooms.

_Cone-shaped. Bell-shaped. Convex. Plane._Raised at center.
Depressed. Funnel form._]

_The common edible mushroom, in button stages, mycelium or
spawn also shown._

Photo by G. F. Atkinson.]

In the common edible species of mushroom (_Agaricus campestris_), the stem is white and almost cylindrical, tapering slightly toward the base; it is solid although the core is not so firm as the outside. When it first pushes above the ground, it is in what is called the “button stage” and consists of a little, rounded cap covered with a membrane which is attached to the stem. Later the cap spreads wide, for it is naturally umbrella-shaped, and it tears loose this membrane, leaving a piece of it attached to the stem; this remnant is called the ring or collar. The collar is very noticeable in many species, but in the common mushroom it soon shrivels and disappears. The cap is at first rounded and then convex; its surface is at first smooth, looking soft and silky; but as the plant becomes old, it is often broken up into triangular scales which are often dark brown; although the color of the cap is usually white or pale brown. The gills beneath the cap are at first white, but later, as the spores mature, they become brownish black because of the ripened spores.

_References_--Mushrooms, a most excellent and practical book with many beautiful pictures, written and illustrated by Professor George F. Atkinson; Henry Holt & Co., N. Y., $3.00; The Mushroom Book, Marshall, fully illustrated, $4.00, Doubleday, Page & Co.; One Thousand American Fungi, McIlvaine, illustrated, Bowen-Merrill Co., $5.00; Our Edible Toadstools and Mushrooms, W. H. Gibson, very fully illustrated, Harper and Bros., $3.50.

LESSON CLXXIX

MUSHROOMS

_Leading thought_--Mushrooms are the fruiting organs of the fungi which grow in the form of threads, spreading in every direction through the food material. The dust which falls from ripe mushrooms is made up of spores which are not true seeds, but which will start a new growth of the fungus.

Photo by George F. Atkinson.]

_Method_--The ideal method would be to study the mushrooms in the field and forest, making an excursion for the purpose of collecting as many species as possible. But the lesson may be given from specimens brought into the schoolroom by pupils, care being taken to bring with them the soil, dead wood or leaves on which they were found growing. After studying one species thus, encourage the pupils to bring in as many others as possible. There are a few terms which the pupils should learn to use, and the best method of teaching them is to place the diagrams shown on pages 708, 711, 712, on the blackboard, and leave them there for a time.

Since mushrooms are especially good subjects for water-color and pencil studies, it would add much to the interest of the work if each pupil, or the school as a whole, should make a portfolio of sketches of all the species found. With each drawing there should be made on a supplementary sheet a spore-print of the species. White paper should be covered very thinly with white of egg or mucilage, so as to hold fast the discharged spores when making these prints for portfolio or herbarium.

_Observations_--1. Where was the mushroom found? If on the ground, was the soil wet or dry? Was it in open fields or in woods? Or was it found on rotten wood, fallen leaves, old trees or stumps, or roots? Were there many or few specimens?

2. Is the cap cone-shaped, bell-shaped, convex, plane, concave, or funnel-form? Has it a raised point at the center? How wide is it?

3. What is the color of the upper surface of the cap when young? When old? Has it any spots of different colors on it? Has it any striate markings, dots or fine grains on its surface? Is its texture smooth or scaly? Is its surface dull, or polished, or slimy? Break the cap and note the color of the juice. Is it milky?

Photo by George F. Atkinson.]

4. Look beneath the cap. Is the under surface divided into plates like the leaves of a book, or is it porous?

5. The plates which may be compared to the leaves of a book are called gills, although they are not for the purpose of breathing, as are the gills of a fish. Are there more gills near the edge of the cap than near the stem? How does this occur? What are the colors of the gills? Are the gills the same color when young as when old? Are the lower edges of the gills sharp, blunt or saw-toothed?

6. Break off a cap and note the relation of the gills to the stem. If they do not join the stem at all they are termed “free.” If they end by being joined to the stem, they are called “adnate” or “adnexed.” If they extend down the stem they are called “decurrent.”

7. Take a freshly opened mushroom, cut off the stem, even with the cap, and set the cap, gills down, on white paper; cover with a tumbler, or other dish to exclude draught; leave it for twenty-four hours and then remove the cover, lift the cap carefully and examine the paper. What color is the imprint? What is its shape? Touch it gently with a pencil and see what makes the imprint. Can you tell by the pattern where this fine dust came from? Examine the dust with a lens. This dust is made up of mushroom spores, which are not true seeds, but which do for mushrooms what seeds do for plants. How do you think the spores are scattered? Do you know that one little grain of this spore dust would start a new growth of mushrooms?

Photo by George F. Atkinson.]

8. Look at the stem. What is its length? Its color? Is it slender or stocky? Is its surface shiny, smooth, scaly, striate or dotted? Has it a collar or ring around it near the top? What is the appearance of this ring? Is it fastened to the stem, or will it slide up and down? Is the stem solid or hollow? Is it swollen at its base? Is its base set in a sac or cup, or is it covered with a membrane which scales off? Do you know that the most poisonous of mushrooms have the sac or the scaly covering at the base of the stem?

9. Examine with a lens the material on which the mushroom was growing; do you see any threads in it that look like mold? Find if you can what these threads do for the mushroom? If you were to go into the mushroom business what would you buy to start your beds? What is mushroom “spawn?”

10. If you can find where the common edible mushrooms grow plentifully, or if you know of any place where they are grown for the market, get some of the young mushrooms when they are not larger than a pea and others that are larger and older. These young mushrooms are called “buttons.” Find by your own investigation the relation between the buttons and the threads. Can you see the gills in the button? Why? What becomes of the veil over the gills as the mushrooms grow large?

11. Do you know the difference between mushrooms and toadstools? Do you know the common edible mushroom when you see it? What characters separate this from the poisonous species? What is the “death cup,” as it is called, which covers the base of the stem of the most common poisonous species?

Photo by G. F. Atkinson.]

PUFFBALLS
_Teacher’s Story_

The puffballs are always interesting to children, because of the “smoke” which issues from them in clouds when they are pressed between thumb and finger. The common species are white or creamy when young; and some of the species are warty or roughened, so that as children we called them “little lambs.” They grow on the ground usually, some in wet, shady places, and others, as the giant species, in grassy fields in late summer. This giant puffball always excites interest, when found. It is a smoothish, white, rounded mass, apparently resting on the grass as if thrown there; when lifted it is seen that it has a connection below at its center, through its mycelium threads, which form a network in the soil. It is often a foot in diameter, and specimens four feet through have been recorded. When its meat is solid and white to the very center, it makes very good food. The skin should be pared off, the meat sliced and sprinkled with salt and pepper and fried in hot fat until browned. All the puffballs are edible, but ignorant persons might mistake the button stages of some of the poisonous mushrooms for little puffballs, and it is not well to encourage the use of small puffballs for the table.

A common species--“the beaker puffball”--is pear-shaped, with its small end made fast to the ground, which is permeated with its vegetative threads.

The interior of a puffball, “the meat,” is made up of the threads and spores. As they ripen, the threads break up so that with the spores they make the “smoke,” as can be seen if the dust is examined through a microscope. The outer wall may become dry and brittle and break open to allow the spores to escape, or one or more openings may appear in it as spore doors. The spores of puffballs were used extensively in pioneer days to stop the bleeding of wounds and especially for nosebleed.

Photo by Verne Morton.]

In one genus of the puffball family, the outer coat splits off in points on maturing, like an orange peel cut lengthwise in six or seven sections but still remaining attached to the base. There is an inner coat that remains as a protection to the spores, so that these little balls are set each in a little star-shaped saucer. These star points straighten out flat or even curl under in dry weather, but when damp they lift up and again envelop the ball to a greater or less extent.

LESSON CLXXX

PUFFBALLS

_A big puffball._]

_Leading thought_--The puffballs are fungi that grow from the threads, or mycelium, which permeate the ground or other matter, on which the puffballs grow. The puffballs are the fruiting organs, and “smoke” which issues from them is largely made up of spores, which are carried off by the wind and sown and planted.

_Method_--Ask the pupils to bring to school any of the globular or pear-shaped fungi in the early stages when they are white, taking pains to bring them on the soil or wood on which they are growing.

_Observations_--1. Where did you find the puffball? On what was it growing? Were there many growing in company? Remove the puffball, and examine the place where it stood with a lens to find the matted and crisscrossed fungus threads.

2. What is the size and shape of the puffball? Is its surface smooth or warty? What is its color inside and outside?

3. Have you ever found the giant puffball, which may become four inches to four feet through? Where was it growing? Have you ever eaten this puffball sliced and fried? Do you know by the looks of the meat when it is fit to eat?

4. If the puffball is ripe, what is its color outside and in? What is the color of its “smoke?” Does the smoke come out through the broken covering of the puffball, or are there one or more special openings to allow it to escape?

5. Puff some of the “smoke” on white paper and examine it with a lens. What do you think this dust is? Of what use is it to the puffball?

6. Have you ever found what are called earth-stars, which look like little puffballs set in star-shaped cups? If you find these note the following things:

a. Of what is the star-shaped base made? Was it always there?
b. Let this star saucer become very dry; how does it act?
c. Wet it; and how does it behave then?
d. Where and how does the spore dust escape from the earth-stars?

7. For what medicinal purpose is the “smoke” of the puffball sometimes used?

THE BRACKET FUNGI

_Teacher’s Story_

Photo by Verne Morton.

_A bracket fungus._]

There are some naturalists who think that one kind of life is as good as another and therefore call all things good. Perhaps this is the only true attitude for the nature lover. To such the bracketlike fungi which appear upon the sides of our forest and shade trees are simply an additional beauty, a bountiful ornamentation. But some of us have become special pleaders in our attitude toward life, and those of us who have come to feel the grandeur of tree life can but look with sorrow upon these fungus outgrowths, for they mean that the doom of the tree is sealed.

There are many species of bracket fungi. Three of these are very common. The gray bracket, gray above and with creamy surface below (_Polyporous applanatus_) is a favorite for amateur etchers, who with a sharp point make interesting sketches upon this naturally prepared plate; this species often grows to great size and is frequently very old. Another species (_P. lucidus_) is in color a beautiful mahogany, or coral-red above and has a peculiar stem from which it depends; the stem and upper surface are polished as if burnished and the lower surface is yellowish white. Another species (_P. sulphurens_) is sulphur yellow above and below; usually many of these yellow brackets are grouped together, their fan-shaped caps overlapping. Many of the shelf fungi live only on dead wood, and those are an aid in reducing dead branches and stumps until they crumble and become again a part of the soil. However, several of the species attack living trees and do great damage. They can gain access to the living tree only through an injured place in the bark, a break caused perhaps by the wind, by a bruise from a falling tree, or more often from the hack of the careless wood-chopper; often they gain entrance through an unhealed knot-hole. To one who understands trees and loves them, their patient striving to heal these wounds inflicted by forces they cannot withstand is truly pathetic. After the wound is made and before the healing is accomplished, the wind may sift into the wound the almost omnipresent spores of these fungi and the work of destruction begins. From the spores grows the mycelium, the fungus threads which push into the heart of the wood getting nourishment from it as they go. When we see wood thus diseased we say that it is rotting, but rotting merely means the yielding up of the body substance of the tree to these voracious fungus threads. They push in radially and then grow upward and downward, weakening the tree where it most needs strength to withstand the onslaught of the wind. Later these parasitic threads may reach the cambium layer, the living ring of the tree trunk, and kill the tree entirely; but many a tree has lived long with the fungus attacking its heartwood. A bracket fungus found by Professor Atkinson was eighty years old; however, this may have shortened the life of the tree a century or more.

After these fungus threads are thoroughly established in the tree, they again seek a wound in the protecting bark where they may push out and build the fruiting organ, which we call the bracket. This may be at the same place where the fatal entry was made, or it may be far from it. The bracket is at first very small and is composed of a layer of honeycomb cells, closed and hard above and opening below--cells so small that we can see the cell openings only with a lens. These cells are not hexagonal like the honeycomb, but are tubes packed together. Spores are developed in each tube. Next year another layer of cells grows beneath this first bracket and extends out beyond it; each year it is thus added to, making it thicker and marking its upper surface with concentric rings around the point of attachment. The creamy surface of the great bracket fungus on which etchings are made, is composed of a layer of these minute spore-bearing tubes. Not all bracket fungi show their age by these annual growths, for some species form new shelves every year, which decay after the spores are ripened and shed.

When once the mycelium of such fungus becomes established, the tree is doomed and its lumber made worthless even though, as sometimes happens, the tree heals its wounds so that the fungus is imprisoned and can never send out fruiting brackets. Thus it is most important to teach the pupils how to protect trees from the attacks of these enemies, which are devastating our forests and which sometimes attack our orchards and shade trees.

As soon as a tree is bruised, the wound should be painted or covered with a coat of tar. If the wind breaks a branch, the splinters left hanging should be sawed off, leaving a smooth stump, and this be painted. While ordinary paint if renewed each year will suffice, experiment has shown that the coat of tar is better and should be used.

Especially should teachers impress on pupils the harm done by careless hacking with axe or hatchet. We shall do an invaluable service in the protection of our forests, if we teach the rising generation the respectful treatment of trees--which is due living organisms whose span of life may cover centuries.

LESSON CLXXXI

BRACKET FUNGI

_Leading thought_--The fungi which we see growing shelflike from trees, are deadly enemies to the trees. Their spores germinate and penetrate at some open wound and the growing fungus weakens the wood.

Method--It is desirable that a tree on which shelf fungus grows should be studied by the class, for this is a lesson on the care of trees. After this lesson the fungus itself may be studied at leisure in the schoolroom.

_Observations_--1. On what kind of a tree is the bracket fungus growing? Is it alive or dead? If living, does it look vigorous or is it decaying?

2. Is the fungus bracket growing against the side of the tree, or does it stand out on a stem?

3. Look at the place where the bracket joined the tree. Does it seem to be a part of the wood?

4. What color is the fungus on its upper surface? How large is it? How thick near the tree? How thick at the edge? Can you detect concentric layers or rings? If it is the large species used for etching, cut down through it with a knife or hatchet and count the layers; this should show its age.

5. Look at the lower surface. How does it appear to the naked eye? If you scratch it with a pin or knife does the bruise show? Examine the surface with a lens and describe what you see. Cut or break the fungus and note that each of these holes is an opening to a little tube. In each of these tubes spores are borne.

6. Have you ever seen toadstools that, instead of having the leaflike gills, have beneath the cap a porous surface like a little honeycomb or like the under side of the shelf fungi?

7. How many kinds of shelf fungi can you find? Which of them is on living trees, and which on stumps or dead wood?

8. If the fungus is on a living tree, then the tree is ruined, for the fungus threads have worked through it and weakened it so that it will break easily and is of no use as lumber. There must have been an open wound in the tree where the fungus entered; see whether you can find this wound. There must also have been a wound where the shelf grew out; see whether you can detect it. If the tree should heal all its wounds after the fungus entered, what would become of the fungus?

9. What does the shelf fungus feed on? What part of it corresponds to the roots and leaves of other plants? What part may be compared to the flowering and fruiting parts of plants?

10. What treatment must we give trees to keep them free from this enemy?

Photo by G. F. Atkinson.]

LESSON CLXXXII

HEDGEHOG FUNGI

There is something mysterious about all fungi, but perhaps none of these wonderful organisms so strangely impresses the observer as the fountainlike masses of creamy white or the branching white coral that we see growing on a dead tree trunk. The writer remembers as a child that the finding of these woodland treasures made her feel as if she were in the presence of the supernatural, as if she had discovered a fairy grotto or a kobold cave. The prosaic name of hedgehog fungi has been applied to these exquisite growths. Their life story is simple enough. The spores falling upon dead wood start threads which ramify within it and feed on its substance, until strong enough to send out a fruiting organ. This consists of a stem, dividing into ascending branches; from these branches, depending like the stalactites in a cave, are masses of drooping spines, the surface of each bearing the spores. And it is so natural for these spines to hang earthward that they are invariably so placed when the tree is in the position in which they grew. There is one species called the “satyr’s beard,” sometimes found on living trees, which is a mere bunch of downward-hanging spines; the corallike species is called _Hydnum coraloides_, and the one that looks like an exquisite white frozen fountain, and may be seen in late summer or early autumn growing from dead limbs or branches, is the bear’s head fungus; it is often eight inches across.

Photo by George F. Atkinson.]

_Observations_--1. These fungi come from a stem which extends into the wood.

2. This stem divides into many branchlets.

3. From these branchlets there hang long fleshy fringes like miniature icicles.

4. These fringes always hang downward when the fungus is in natural position.

5. These fringes bear the spores.

LESSON CLXXXIII

THE SCARLET SAUCER (_Sarcocypha coccinea_)

The heart of the child, searching the woods for hepaticas--woods where snow banks still hold their ground on north slopes--is filled with delight at finding these exquisite saucerlike fungi. They are more often found on fallen rotting branches which are more or less buried in leaves, and there are likely to be several of different sizes on the same stick. When they grow unhindered and while they are young, they are very perfectly saucer-shaped and range from the size of a pea to an inch or two across. But the larger they are the more likely are they to be distorted, either by environment or by the bulging of rapid growth. The under side of the saucer is beautifully fleshlike in color and feeling and is attached at the middle to the stick. The inside of the saucer is the most exquisite scarlet shading to crimson. This crimson lining bears the spores in little sacs all over its surface.

_Observations_--1. Where did you find the fungus?

2. What is the shape of the saucer? How large is it? Is it regular and beautiful or irregular and distorted?

3. What is the color inside?

4. What is the color outside?

5. Turn the one you bring in bottom side up--that is, scarlet side down--on a piece of white paper, and see whether you can get a spore harvest.

LESSON CLXXXIV

THE MORELS

Photo by George F. Atkinson.]

In May or June in open, damp places, as orchards or the moist fence corners of meadows, the morels may be found. This mushroom family contains no member that is poisonous, and the members are very unlike any other family in appearance. They are very pretty with their creamy white, thick, swollen stems and a cap more or less conical, made up of the deep-celled meshes of an unequal network. The outside edges of the network are yellowish or brownish when the morel is young and edible, but later turn dark as the spores develop. In some species the stems are comparatively smooth and in others their surface is more or less wrinkled. The spores are borne in the depressions of the network. These mushrooms should not be eaten after the cells change from creamy white to brownish.

_Observations_--1. Where did you find the morels?

2. Describe the stem. Is it solid or hollow? Is it smooth or rough?

3. What is the shape of the cap? How does it look? What color is the outer edge of the network? What is the color within the meshes?

4. Take one of these fungi, lay it on a sheet of white paper, and note the color of the spores.

LESSON CLXXXV

THE STINKHORNS

Photo by George F. Atkinson.]

To give a nature-study lesson on the stinkhorn is quite out of the question, for the odor of these strange growths is so nauseating that even to come near to one of them in the garden is a disagreeable experience. The reason for mentioning them at all is because of the impression made by them that most mushrooms are ill smelling, which is a slander.

It is a pity that these fungi are so offensive that we do not care to come near enough to them to admire them, for they are most interesting in appearance. The scientific name of our commonest genus when translated means “the net bearers,” and it is a most appropriate name. The stout, white stem is composed of network without and within. The outer covering of the stem seems to tear loose from the lower portion as the stem elongates, and is lifted so that it hangs as a veil around the bottom of the bell-shaped cap, which is always covered with a pitted network. The mycelium, or spawn, of the stinkhorn consists of strands which push their way through the ground or through the decaying vegetable matter on which they feed. On these strands are produced the stinkhorns, which at first look like eggs; but later the top of the egg is broken, and the strange horn-shaped fungus pushes up through it. The spores are borne in the chambers of the cap, and when ripe the substance of these chambers dissolves into a thick liquid in which the spores float. The flies are attracted by the fetid odor and come to feast upon these fungi and to lay their eggs within them, and incidentally they carry the spores away on their brushy feet, and thus help to spread the species.

MOLDS

_Teacher’s Story_

It is lucky for our peace of mind that our eyes are not provided with microscopic lenses, for then we should know that the dust, which seems to foregather upon our furniture from nowhere, is composed of all sorts of germs, many of them of the deadly kind. The spores of mold are very minute objects, the spore-cases being the little white globes, not larger than the head of a small pin which we see upon mold, yet each of these spore-cases breaks and lets out into the world thousands of spores, each one ready and anxious to start a growth of mold and perfectly able to do it under the right conditions; almost any substance which we use for food, if placed in a damp and rather dark place, will prove a favorable situation for the development of the spore which swells, bursts its wall and sends out a short thread. This gains nourishment, grows longer and branches, sending out many threads, some of which go down into the nutritive material and are called the mycelium. While these threads, in a way, act like roots, they are not true roots. Presently the tip ends of the threads, which are spread out in the air above the bread or other material, begin to enlarge, forming little globules; the substance (protoplasm) within them breaks up into little round bodies, and each develops a cell wall and thus becomes a spore. When these are unripe they are white but later, they become almost black. In the blue mold the spores are borne in clusters of chains, and resemble tiny tassels instead of growing within little globular sacs.

Molds, mildews, blights, rusts and smuts are all flowerless plants and, with the mushrooms, belong to the great group of fungi. Molds and mildews will grow upon almost any organic substance, if the right conditions of moisture are present, and the temperature is not too cold.

Molds of several kinds may appear upon the bread used in the experiments for this lesson. Those most likely to appear are the bread mold--consisting of long, white threads tipped with white, globular spore-cases, and the green cheese-mold--which looks like thick patches of blue-green powder. Two others may appear, one a smaller white mold with smaller spore-cases, and a black mold. However, the bread mold is the one most desirable for this lesson, because of its comparatively large size. When examined with a lens, it is a most exquisite plant. The long threads are fringed at the sides, and they pass over and through each other, making a web fit for fairies--a web all beset with the spore-cases, like fairy pearls. However, as the spores ripen, these spore-cases turn black, and after a time so many of them are developed and ripened that the whole mass of mold is black. The time required for the development of mold varies with the temperature. For two or three days nothing may seem to be happening upon the moist bread; then a queer, soft whiteness appears in patches. In a few hours or perhaps during the night, these white patches send up white fuzz which is soon dotted with tiny pearl-like spore-cases. At first there is no odor when the glass is lifted from the saucer, but after the spores ripen, the odor is quite disagreeable.

The special point to teach the children in this lesson is that dryness and sunlight are unfavorable to the development of mold; and it might be well to take one of the luxuriant growths of mold developed in the dark, uncover it and place it in the sunlight, and see how soon it withers. The lesson should also impress upon them that dust is composed, in part, of living germs waiting for a chance to grow.

LESSON CLXXXVI

MOLDS

_Leading thought_--The spores of mold are everywhere and help to make what we call dust. These spores will grow on any substance which gives them nourishment, if the temperature is warm, the air moist and the sunlight is excluded.

_Method_--Take bread in slices two inches square, and also the juice of apple sauce or other stewed fruit. Have each pupil, or the one who does the work for the class, provided with tumblers and saucers. Use four pieces of bread cut in about two-inch squares, each placed on a saucer; moisten two and leave the other two dry. With a feather or the finger take some dust from the woodwork of the room or the furniture and with it lightly touch each piece of bread. Cover each with a tumbler. Set one of the moistened pieces in a warm, dark place and the other in a dry, sunny place. Place a dry piece in similar situations. Let the pupils examine these every two or three days.

Put fruit juice in a saucer, scatter a little dust over it and set it in a warm, dark place. Take some of the same, do not scatter any dust upon it, cover it safely with a tumbler and put it in the same place as the other. A lens is necessary for this lesson, and it is much more interesting for the pupils if they can see the mold under a microscope with a three-fourths objective.

_Observations_--1. When does the mold begin to appear? Which piece of bread showed it first? Describe the first changes you noticed. What is the color of the mold at first? Is there any odor to it?

2. At what date did the little branching mold-threads with round dots appear? Is there an odor when these appear? What are the colors of the dots, or spore-cases, at first? When do these begin to change color? How does the bread smell then? What caused the musty odor?

3. Did the mold fail to appear on any of the pieces of bread? If so, where were these placed? Were they moist? Were they exposed to the sunlight?

4. Did more than one kind of mold appear on the bread? If so, how do you know that they are different kinds? Are there any pink or yellow patches on the bread? If so, these are made by bacteria and not by mold.

5. From the results of the experiments, describe in what temperature mold grows best. In what conditions of dryness or moisture? Does it flourish in the sunlight or in the dark?

6. Where does the mold come from? What harm does it do? What should we do to prevent the growth of mold? Name all of the things on which you have seen mold or mildew growing.

7. Examine the mold through a microscope or a lens. Describe the threads. Describe the little round spore-cases. Look at some of the threads that have grown down into the fruit juice. Are they like the ones which grow in the air?

8. If you have a microscope cut a bit of the mold off, place it in a drop of water on a glass slide, put on a cover-glass. Examine it with a three-fourths objective, and describe the spores and spore-cases.

_1. Cholera bacillus._

_2. Typhoid bacillus._

_3. A bacillus found in sewage. These are all enlarged 2000
times._

_4. Bacteria from tubercle on white sweet clover, much
enlarged._

_5 and 6. Bacteria of lactic acid ferments in ripening of
cheese, much enlarged._
]

BACTERIA

_Teacher’s Story_

The yellow, pink or purple spots developed upon the moist and moldy bread are caused by bacteria and yeast. Bacteria are one-celled organisms now classed as plants; they are the smallest known living beings, and can only be seen through a high power microscope.

Bacteria grow almost everywhere--in the soil, on all foods and fruits, in the water of ponds, streams and wells, in the mouths and stomachs of human beings, and in fact in almost all possible places, and occur in the air. Most of them are harmless, some of them are useful, and some produce disease in both plants and animals, including man.

What bacteria do would require many large volumes to enumerate. Some of them develop colors or pigments; some produce gases, often ill-smelling; some are phosphorescent; some take nitrogen from the air and fix it in the soil; some produce putrefaction; and some produce disease. Nearly all of the “catching diseases” are produced by bacteria. Diphtheria, scarlet fever, typhoid fever, consumption, influenza, grippe, colds, cholera, lockjaw, leprosy, blood poisoning and many other diseases are the result of bacteria. On the other hand, many of the bacteria are beneficial to man. Some forms ripen the cream before churning, others give flavor to butter; while some are an absolute necessity in making cheese. The making of cider into vinegar is the work of bacteria; some clear the pollution from ponds and streams; some help to decompose the dead bodies of animals, so that they return to the dust whence they came.

We have in our blood little cells whose business it is to destroy the harmful bacteria which get into the blood. These little fighting cells move everywhere with our blood, and if we keep healthy and vigorous by right living, right food and exercise, these cells may prove strong enough to kill the disease germs before they harm us. Direct sunlight also kills some of the bacteria. Seven or eight minutes exposure to bright sunlight is said to kill the germs of tuberculosis. Exposure to the air is also a help in subduing disease germs. Bichloride of mercury, carbolic acid, formaldehyde and burning sulphur also kill germs, and may be applied to clothing or to rooms in which patients suffering from these germ diseases have been. We can do much to protect ourselves from harmful bacteria by being very clean in our persons and in our homes, by bathing frequently and washing our hands with soap often. We should eat only pure and freshly cooked food, we should get plenty of sleep and admit the sunlight to our homes; we should spend all the time possible in the open air and be careful to drink pure water. If we are not sure that the water is pure, it should be boiled for twenty minutes and then cooled for drinking.

In Experiment A the milk vials and the corks are all boiled, so that we may be sure that no other bacteria than the ones we chose are present, since boiling kills these germs. As soon as the milk becomes discolored we know that it is full of bacteria.

Experiment B shows that bacteria can be transplanted to gelatin, which is a material favorable for its growth. But the point of this experiment is to show the child that a soiled finger will have upon it germs which, by growing, cloud the gelatin. They should thus learn the value of washing their hands often or of keeping their fingers out of their mouths.

Experiment C shows the way the destructive bacteria attack the potato. The discolored spots show where the decay begins, and the odor is suggestive of decay. If a potato thus attacked is put in the bright sunlight the bacteria are destroyed, and this should enforce the moral of the value of sunshine.

_References_--The Story of the Bacteria; Dust and its Dangers, M. T. Prudden, Putnam’s. Bacteria in Relation to Country Life, Lipman.

LESSON CLXXXVII

BACTERIA

_Leading thought_--Bacteria are such small plants that we cannot see them without the aid of a microscope, but they can be planted and will grow. The object of this lesson is to enforce cleanliness.

_Method_--_Experiment A_--The bread used for the mold experiment is likely to develop spots of yellow, red or purple upon it, and cultures from these spots may be used in this lesson as follows: Take some vials, boil them and their corks, and nearly fill them with milk that has been boiled. Take the head of a pin or hairpin, sterilize the point by holding in a flame, let it cool, touch one of the yellow spots on the bread with the point, being careful to touch nothing else, and thrust the point with the bacteria on it into the milk; then cork the vials.

_Experiment B_--Prepare gelatin as for the table but do not sweeten. Pour some of this gelatin on clean plates or saucers. After it has cooled let one of the children touch lightly the gelatin in one saucer for a few seconds with his soiled finger. Note the place. Ask him to wash his hands thoroughly with soap and then apply a finger to the surface of the gelatin in the other plate. Cover both plates to keep out the dust and leave them for two or three days in a dark place. The plates touched by the soiled finger will show a clouded growth in the gelatin; the other plate will show a few irregular, scattered growths or none.

_Experiment C_--Take a slice of boiled potato, place in a saucer, leave it uncovered for a time or blow dust upon it, label with date, then cover with a tumbler to keep from drying and place in a cool, somewhat dark place.

The pupils should examine all these cultures every day and make the following notes:

_Experiment A_--How soon did you observe a change in the color of the milk? How can you tell when the milk is full of the bacteria? How do you know that the bacteria in the milk was transplanted by the pin?

_Experiment B_--Can you see that the gelatin is becoming clouded where the soiled finger touched it? This is a growth of the bacteria which were on the soiled finger.

_Experiment C_--What change has taken place in the appearance of the slice of potato? Are there any spots growing upon it? What is the odor? What makes the spots? Describe the shape of the spots. The color. Are any of them pimple-shaped? Make a drawing of the slice of potato showing the bacteria spots. What are the bacteria doing to the potato? Take a part of the slice of potato with the bacteria spots upon it, and put it in the sunshine. What happens? Compare this with the part kept in the dark.

After this lesson the children should be asked the following questions.

1. Why should the hands always be washed before eating?

2. Why should the finger nails be kept clean?

3. Why should we never bite the finger nails nor put the fingers in the mouth?

4. Why should we never put coins in the mouth?

5. Why should wounds be carefully cleansed and dressed at once?

6. Why should clothing, furniture and the house be kept free from dust?

7. Why should sweeping be done as far as possible without raising dust?

8. Why are hardwood floors more healthful than carpets?

9. Why is a damp cloth better than a feather duster for removing dust?

10. Why should the prohibition against spitting in public places be strictly enforced?

11. Why should the dishes, clothes and other articles used by sick persons be kept distinctly separate from those used by well members of the family?

12. Why should food not be exposed for sale on the street?

13. Why, during an epidemic, should water be boiled before drinking?

* * * * *

“_This habit of looking first at what we call the beauty
of objects is closely associated with the old conceit that
everything is made to please man: man is only demanding his
own. It is true that everything is man’s because he may use it
or enjoy it, but not because it was designed and ‘made’ for
‘him’ in the beginning. This notion that all things were made
for man’s special pleasure is colossal self-assurance. It has
none of the humility of the psalmist, who exclaimed, ‘What is
man, that thou art mindful of him?’_”

“_‘What were these things made for, then?’ asked my friend.
Just for themselves! Each thing lives for itself and its kind,
and to live is worth the effort of living for man or bug. But
there are more homely reasons for believing that things were
not made for man alone. There was logic in the farmer’s retort
to the good man who told him that roses were made to make man
happy. ‘No, they wa’n’t’, said the farmer, ‘or they wouldn’t
a had prickers.’ A teacher asked me what snakes are ‘good
for.’ Of course there is but one answer: they are good to be
snakes._”
--“THE NATURE STUDY IDEA”, L. H. BAILEY.

Photo by G. K. Gilbert. Courtesy of U. S. Geological Survey.]

TREE STUDY

_Teacher’s Story_

“_I wonder if they like it--being trees?
I suppose they do.
It must feel so good to have the ground so flat,
And feel yourself stand straight up like that.
So stiff in the middle, and then branch at ease,
Big boughs that arch, small ones that bend and blow,
And all those fringy leaves that flutter so.
You’d think they’d break off at the lower end
When the wind fills them, and their great heads bend.
But when you think of all the roots they drop,
As much at bottom as there is on top,
A double tree, widespread in earth and air,
Like a reflection in the water there._”
--“TREE FEELINGS” BY CHARLOTTE PERKINS STETSON.

Natural is our love for trees! A tree is a living being, with a life comparable to our own. In one way it differs from us greatly: it is stationary, and it has roots and trunk instead of legs and body; it is obliged to wait to have what it needs come to it, instead of being able to search the wide world over to satisfy its wants.

THE PARTS OF THE TREE

The _head_, or _crown_, is composed of the branches as a whole, which in turn are composed of the larger and smaller branches and twigs. The _spray_ is the term given to the outer twigs, the finest divisions of the trunk, which bear the leaves and fruit. The branches are divisions of the _bole_, or _trunk_, which is the body, or stem, of the tree. The bole, at the base, divides into roots, and the roots into rootlets, which are covered with root-hairs. It is important to understand what each of the parts of a tree’s anatomy does to help carry on the life of the tree.

The roots, which extend out in every direction beneath the surface of the ground, have two quite different offices to perform: First, they absorb the water which contains the tree food dissolved from the soil; second, they hold the tree in place against the onslaught of the winds. If we could see a tree standing on its head with its roots spread in the air in the same manner as they are in the ground, we could then better understand that there is as much of the tree hidden below ground as there is in sight above ground, although of quite different shape, being flatter and in a more dense mass. The roots seem to know in which direction to grow to reach water; thus, the larger number of the roots of a tree are often found to extend out toward a stream flowing perhaps some distance from the tree; when they find plenty of food and water the rootlets interlace forming a solid mat. On the Cornell Campus are certain elms which, every six or seven years, completely fill and clog the nearby sewers; these trees send most of their roots in the direction of the sewer pipe. The fine rootlets upon the tree-roots are covered with root-hairs, which really form the mouths by which the liquid food is taken into the tree.

To understand how firm a base the roots form to hold up the tall trunk, we need to see an uprooted tree. The great roots seem to be molded to take firm grasp upon the soil. It is interesting to study some of the “stump fences” which were made by our forefathers, who uprooted the white pines when the land was cleared of the primeval forest, and made fences of their widespreading but rather shallow extending roots. Many of these fences stand to-day with branching, out-reaching roots, white and weather-worn, but still staunch and massive as if in memory of their strong grasp upon the soil of the wilderness.

The trunk, or bole, or stem of the tree has also two chief offices: It holds the branches aloft, rising to a sufficient height in the forest so that its head shall push through the leaf canopy and expose the leaves to the sunlight. It also is a channel by which the water containing the food surges from root to leaf and back again through each growing part. The branches are divisions of the trunk, and have the same work to do.