. Science of plant life, a high school botany treating of the plant and its relation to the environment. Botany. Bacteria and Fungi 261 however, and get their food either from organic matter or from living plants. The plant body is always made up of filaments like those of the algae. In the higher forms, like the mushrooms, the filaments are massed together into a com- pact, solid structure. The yeasts and molds, and most of the mushrooms, are saprophytes; the smuts, rusts, and some of the mildews are parasites upon the higher plants, and they cause serious losses to the farmer and gardener. A
. Science of plant life, a high school botany treating of the plant and its relation to the environment. Botany. Bacteria and Fungi 261 however, and get their food either from organic matter or from living plants. The plant body is always made up of filaments like those of the algae. In the higher forms, like the mushrooms, the filaments are massed together into a com- pact, solid structure. The yeasts and molds, and most of the mushrooms, are saprophytes; the smuts, rusts, and some of the mildews are parasites upon the higher plants, and they cause serious losses to the farmer and gardener. A few of the mushrooms are edible and furnish small quantities of food for animals and man. The yeasts. In the making of bread, yeasts are of primary importance. They are small, one-celled plants that multi- ply very rapidly, and when properly mixed with flour and water they develop in all parts of the dough. The yeasts have within them enzymes which change part of the sugar that is present into carbon dioxid and alcohol. The carbon dioxid acciunulates in bubbles and makes the dough light. When the dough is put into a hot oven the alcohol is vaporized, and together with the carbon dioxid it is driven off into the air. The high temperature kills the yeast, bakes the dough, and changes some of the starch into its soluble form, dextria, which makes it more readily digestible. Sour bread is pro- duced when the yeast that is added contains acid-forming bacteria which change part of the alcohol into acetic acid. Yeasts and bacteria are the tVi <â VianCTp fniif- ^'"^ ^^^' Yeast ceUs and chains of cells. orgdi 5 Above are three cells, each containing four juice into cider and vinegar, resting Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Transeau, Edgar Nelson, 1875-1960. Yonkers-on-Hudson, N. Y.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbotany, bookyear1921
