. A text-book of botany for secondary schools. Botany. 134 A TEXT-BOOK OP BOTANY The most important relations of bacteria to man maj- be groupetl under the following three heads: (1) those that induce fermentation; (2) those that induce disease; (3) and those that fix nitrot/en. (1) Bacteria that induce fermentation.—In general, fer- mentation is the decomposition of carboln-drates and proteids by the action of living forms directly or by the enzymes (§ 47) which they produce, and conspicuous among these forms are bacteria. When proteids (meat, etc.) con- taining nitrogen and sulphur are decom
. A text-book of botany for secondary schools. Botany. 134 A TEXT-BOOK OP BOTANY The most important relations of bacteria to man maj- be groupetl under the following three heads: (1) those that induce fermentation; (2) those that induce disease; (3) and those that fix nitrot/en. (1) Bacteria that induce fermentation.—In general, fer- mentation is the decomposition of carboln-drates and proteids by the action of living forms directly or by the enzymes (§ 47) which they produce, and conspicuous among these forms are bacteria. When proteids (meat, etc.) con- taining nitrogen and sulphur are decomposed in this way, offensive gases are hberated, such decomposition being often called putrefaction. When the word fermentation is ordinarily used it refers to the decomposition of sugars in. C£<t) ^ B / C Fig. 122.—Certain bacteria of fermentation and disease: bacteria of souring milk {--1}, of vinegar (i?), of diphtheria {('), of tetanus or lockjaw (Z)); (' and D show the formation of the so-called " ;—After Fischer. solution, as in various fruit juices, which breaks them up into alcohol and carbon dioxide, the latter rising as bubbles through the solution, which is then said to be working. Such fermentations are produced chiefly bj^ yeasts, which are considered in the next section; but bacteria are con- cerned in the souring of milk and of fruit juices and in the manufacture of vinegar (Fig. 122). These saproph3'tic bacteria that induce fermentation and putrefaction are of much service as scavengers, being the chief agents in the destruction of dead bodies. The various processes for. 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 Coulter, John Merle, 1851-1928. New York, D. Appleton
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1906
