32. - - The effect of drying. Place under separate bell glass two
slices of bread, one of which is damp, either naturally or slightly
^•Preparation of gelatin culture media: To 100 grams of gelatin add goo cc. of
water and about 5 grams of Liebig's Extract of Beef and cook in double boiler for
5 minutes. While still hot filter the material through absorbent cotton. In using
absorbent cotton for this purpose, a large funnel should be used and the absorbent
cotton wet with hot water, placed in it. The liquid is poured into the cotton and it
will run through readily, coming out as a tolerably clear solution. Some of the fil-
tered jelly is to be placed in sterilized flasks and some in test tubes, about 10 cc. in
each. Plug the flasks and test tubes with cotton and steam the jelly in a common
steamer for 30 minutes. At the end of 24 hours it should again be placed in the
steamer and steamed for half an hour. Once more set it aside for 24 hours and upon
the third day steam it again for half an hour and cool. Material thus prepared
should give a clear, slightly brownish jelly, which, if properly sterilized, will keep
indefinitely. It should be acid to litmus paper.
CANNING AND PRESERVING 29
moistened with water, and the other dried. Leave for two or three
days and notice the effect of drying in preventing the growth of
molds. If one slice remains dry, no molds will grow upon it though
the other soon becomes covered.
33. - - The effect of boiling temperature. In each of two test tubes
of gelatin place a small quantity of mold spores. Melt the gelatin
in the tubes at as low a heat as will melt it. Pour the contents of
one tube into a petri dish and cover at once. Place the other tube in
a beaker of boiling water and allow the water to boil briskly for half
an hour, after which the gelatin is to be poured into a petri dish and
treated like that in the first tube. Set both dishes aside for mold
growth and examine at intervals for several days, noticing whether
molds develop in both dishes or only in the first. If they grow in
both, note the relative abundance in the two dishes.
34. - - Effect of low temperature. Prepare two plates of hardened
gelatin and sow mold spores upon the surface of each. Leave one
in the ordinary room temperature and place the other in an ice chest
or some other place where the temperature is low. Compare day by
day, and determine the effect of low temperature in checking or
stopping mold growth. Do any molds grow upon the dish placed
in the ice chest ?
35. - - Effect of air currents. Moisten a slice of bread and sow
mold spores upon it, or allow it to mold spontaneously under a bell
glass. After it shows a luxuriant growth of mold, remove the bell
glass and leave it exposed to brisk currents of the air. Notice how
the growth of the mold ceases and the delicate mycelium flattens
down close to the bread.
Page 15
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
32. - - The effect of drying. Place under separate bell glass two slices of bread, one of which is damp, either naturally or slightly
^•Preparation of gelatin culture media: To 100 grams of gelatin add 600 cc. of water and about 5 grams of Liebig's Extract of Beef and cook in double boiler for 5 minutes. While still hot filter the material through absorbent cotton. In using absorbent cotton for this purpose, a large funnel should be used and the absorbent cotton wet with hot water, placed in it. The liquid is poured into the cotton and it will run through readily, coming out as a tolerably clear solution. Some of the filtered jelly is to be placed in sterilized flasks and some in test tubes, about 10 cc. in each. Plug the flasks and test tubes with cotton and steam the jelly in a common steamer for 30 minutes. At the end of 24 hours it should again be placed in the steamer and steamed for half an hour. Once more set it aside for 24 hours and upon the third day steam it again for half an hour and cool. Material thus prepared should give a clear, slightly brownish jelly, which, if properly sterilized, will keep indefinitely. It should be acid to litmus paper.
moistened with water, and the other dried. Leave for two or three days and notice the effect of drying in preventing the growth of molds. If one slice remains dry, no molds will grow upon it though the other soon becomes covered.
33. - - The effect of boiling temperature. In each of two test tubes of gelatin place a small quantity of mold spores. Melt the gelatin in the tubes at as low a heat as will melt it. Pour the contents of one tube into a petri dish and cover at once. Place the other tube in a beaker of boiling water and allow the water to boil briskly for half an hour, after which the gelatin is to be poured into a petri dish and treated like that in the first tube. Set both dishes aside for mold growth and examine at intervals for several days, noticing whether molds develop in both dishes or only in the first. If they grow in both, note the relative abundance in the two dishes.
34. - - Effect of low temperature. Prepare two plates of hardened gelatin and sow mold spores upon the surface of each. Leave one in the ordinary room temperature and place the other in an ice chest or some other place where the temperature is low. Compare day by day, and determine the effect of low temperature in checking or stopping mold growth. Do any molds grow upon the dish placed in the ice chest ?
35. - - Effect of air currents. Moisten a slice of bread and sow mold spores upon it, or allow it to mold spontaneously under a bell glass. After it shows a luxuriant growth of mold, remove the bell glass and leave it exposed to brisk currents of the air. Notice how the growth of the mold ceases and the delicate mycelium flattens down close to the bread.