Describe briefly the naked eye appearance of these various molds
that appear in the laboratory.
26. - - Mold on bread. Place several slices of bread under a bell
glass or any dish that will protect it from evaporation. Battery
jars, large beakers, or even common bowls will answer. Moisten the
bread with water and put aside in a warm place (8o°-9O° F.). After
two or three days the bread will usually show signs of white mold.
Allow the mold to grow until some color appears and then determine,
if possible, whether there are more than one species of mold on the
bread.
27. - - Molds on different foods. Under separate bell glasses place
bits of cheese, some pieces of lemon, and a bit of banana. Each of
these should be moist. Cover and put aside dish as in the last experi-
ment. Molds will grow in a few7 days, but probably different spe-
cies will grow upon the different materials. Compare the molds and
determine how many kinds can be seen.
28. - - Experiment to show the mycelium. Place a little fruit juice,
such as may be obtained from canned fruit, in two tubes or in
homoeopathic vials and drop a few mold spores from the last experi-
ment, or a little dust from the floor upon the surface of the liquid.
Set aside to grow and notice how the molds spread and send fine
threads into the liquid. Later notice that colored masses of spores
grow in the air upon the surface of the liquid but not in the liquid
below.
29. - - Spores. After the molds of the previous experiments have
begun to produce spores, as shown by the appearance of some color,
remove a little spore material from the surface with a knife blade or
a platinum wire and examine under a microscope. For this purpose
a compound microscope is necessary, since the spores are very small.
30. - - Growth of mold from spores. Moisten a bit of bread and
transfer with a platinum wire a little bit of the spore mass from a
vigorously growing mold to the surface of the bread. Cover with
28 LABORATORY MANUAL OF FOODS AND COOKERY
a bell glass and set aside for growth. Examine every day and note
that molds start from the points where the bread was inoculated with
the mold spores.
31. - - Mold spores in dust. Melt gelatin l in 7 prepared test tubes,
and pour it from each into sterilized petri dishes. Replace the cover
upon the dish and allow the gelatin to harden. Label the petri
dishes A, B, C, D, E, F, and G. Proceed as follows:
A. Sweep a little dust from the floor and scatter over the
prepared gelatin in A. Replace the cover and allow the dish to re-
main in a cupboard until molds begin to grow. Note the number of
hours or days until a growth appears. Obtain dust from the follow-
ing sources and proceed as in A.
B. Dust from a crack in the flour.
C. Shake a dry duster over the gelatin.
D. Shake a damp duster over the gelatin.
E. Shake the hem of a skirt over the gelatin.
F. Expose a plate of gelatin to the air of the room while
sweeping.
G. Expose a plate of gelatin to the air of the room 2 hours
after sweeping and dusting thoroughly.
NOTE : The above experiments may be performed using moist bread instead
of petri dishes of gelatin, but the results are not as impressive.
Bread can be used, however, if gelatin is not at hand.
Page 14
Presented as published in 1916. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
AI-modernized reading of the original text
Describe briefly the naked eye appearance of these various molds that appear in the laboratory.
26. - - Mold on bread. Place several slices of bread under a bell glass or any dish that will protect it from evaporation. Battery jars, large beakers, or even common bowls will answer. Moisten the bread with water and put aside in a warm place (8o°-9O° F.). After two or three days the bread will usually show signs of white mold. Allow the mold to grow until some color appears and then determine, if possible, whether there are more than one species of mold on the bread.
27. - - Molds on different foods. Under separate bell glasses place bits of cheese, some pieces of lemon, and a bit of banana. Each of these should be moist. Cover and put aside dish as in the last experiment. Molds will grow in a few days, but probably different species will grow upon the different materials. Compare the molds and determine how many kinds can be seen.
28. - - Experiment to show the mycelium. Place a little fruit juice, such as may be obtained from canned fruit, in two tubes or in homoeopathic vials and drop a few mold spores from the last experiment, or a little dust from the floor upon the surface of the liquid. Set aside to grow and notice how the molds spread and send fine threads into the liquid. Later notice that colored masses of spores grow in the air upon the surface of the liquid but not in the liquid below.
29. - - Spores. After the molds of the previous experiments have begun to produce spores, as shown by the appearance of some color, remove a little spore material from the surface with a knife blade or a platinum wire and examine under a microscope. For this purpose a compound microscope is necessary, since the spores are very small.
30. - - Growth of mold from spores. Moisten a bit of bread and transfer with a platinum wire a little bit of the spore mass from a vigorously growing mold to the surface of the bread. Cover with
a bell glass and set aside for growth. Examine every day and note that molds start from the points where the bread was inoculated with the mold spores.
31. - - Mold spores in dust. Melt gelatin l in 7 prepared test tubes, and pour it from each into sterilized petri dishes. Replace the cover upon the dish and allow the gelatin to harden. Label the petri dishes A, B, C, D, E, F, and G. Proceed as follows:
A. Sweep a little dust from the floor and scatter over the prepared gelatin in A. Replace the cover and allow the dish to remain in a cupboard until molds begin to grow. Note the number of hours or days until a growth appears. Obtain dust from the following sources and proceed as in A.
B. Dust from a crack in the flour.
C. Shake a dry duster over the gelatin.
D. Shake a damp duster over the gelatin.
E. Shake the hem of a skirt over the gelatin.
F. Expose a plate of gelatin to the air of the room while sweeping.
G. Expose a plate of gelatin to the air of the room 2 hours after sweeping and dusting thoroughly.
NOTE : The above experiments may be performed using moist bread instead of petri dishes of gelatin, but the results are not as impressive. Bread can be used, however, if gelatin is not at hand.