. Western agriculture. Figure 19.—Yeast. MICROSCOPIC PLANTS 53. a certain temperature, which varies greatly with differentspecies. Some will develop vigorously at 14 degrees Centi-grade; others at 40 degrees Centigrade; most, however,demand a medium temperature. Some will develop in thepresence of air; others demand the absence of air. We thushave two great groups established: the so-called aerobes and the anaerobes—-the formerrequiring the presence, thelatter the absence, of air. Light is also an importantfactor. Direct sunlight isgermicidal; that is, it will killthe organisms if applied con-
. Western agriculture. Figure 19.—Yeast. MICROSCOPIC PLANTS 53. a certain temperature, which varies greatly with differentspecies. Some will develop vigorously at 14 degrees Centi-grade; others at 40 degrees Centigrade; most, however,demand a medium temperature. Some will develop in thepresence of air; others demand the absence of air. We thushave two great groups established: the so-called aerobes and the anaerobes—-the formerrequiring the presence, thelatter the absence, of air. Light is also an importantfactor. Direct sunlight isgermicidal; that is, it will killthe organisms if applied con-tinuously. Diffused light isinjurious. Electric light issupposed to have the sameeffect as sunlight. Bacteriathrive best in darkness. TheX-ray is known to destroyliving tissue on long exposureand bacteria cannot be moreresistant. The X-ray is used in the treatment of microbialdiseases of the skin. On account of the necessity of definite conditions whichvary with the different species, there have grown up whatare called bacterial flora, that is, groups of or
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectagriculture, bookyear
