slide. Cover with a cover slip. Observe firstunderlow power, and thenunder
high power of your microscope.
You will observe:Underhigh power the black spots willappearasround
cases filled with smaller black spots. The grey fuzz is a branchingstemlike
growththatholds the black cases to the bread.
The balloon-likesacscontainingthe small black specks arespore cases.
The tiny black spots are theactualsporesofmould. They are very light and
arecarriedaboutby aircurrents. They often settle in dust.
When abreadmouldspore lands on a pieceofmoistbread,it will send
outtubelike stems (the grey fuzz) and will grow into a newmouldplant.
The air is always filled with spores ofbreadmould. But they need food
andmoisturefor successfulgrowth;a piece of moist breadprovidesjustthe
conditionsunderwhich these spores thrive.
Astrangeand fascinating discovery was made by SirAlexanderFleming,
a Scottishscientist, beforeWorldWar II. He found thata certainkind of
breadmouldproducesa liquid which has the power to destroy some disease-
causing bacteria. He called this liquidpenicillin. Themouldthatproduces
penicillin andother"wonderdrugs"is now grown inlaboratoriesand used in
medicines to treat (and often to cure) such diseases as tuberculosis and
pneumonia.EXAMINING EDIBLE MUSHROOMS
Materials: Fresh mushrooms, a sharp paringknife (with permission to
use it), kitchenpapertowelling.
Follow this procedure: Firstobserve the wholemushroom. Then cut off
the cap andturnit sothatyou can see the underside.
You will observe:The entire mushroomis a shade ranging from tan to
brown. There are thin tissuesthatlook like theseparatedpagesofa bookon
theundersurfaceofthe cap.
The cap rests on a thick, fleshy, stem-likepartthatgrows securely in rich,
moist, leaf-covered soil in shaded forest land.Themushroomis called afungus. Itcontainsno green coloring matter,
orchlorophyll;therefore itcannotmanufactureits own food. Itgets its food
from the deadplantmatterin which it grows. Italso gets itsmoisturefrom the
rich soil in which it grows.
The page-likestructureson the underside of themushroomcapcontain
small spores. When themushroomis fully grown, these sporesburstoutof