. The essentials of botany. Botany. 8 BOTANt. decrease, and every time the process occurs there the result is but half as many cells as before. Practical Studies.—(a) Carefully scrape ofE (after moistening with a drop of alcohol) a little of the white, mouldy growth on lilac-leaves, known as LilaaBlight; mount it in water, adding a very little potas- sic hydrate. Some of the threads will show the formation of new cells (spores in this case) by fission. Other kinds of blights, as for example that on grass leaves or that common on the leaves of cherry- sprouts, furnish equally good examples. (Se
. The essentials of botany. Botany. 8 BOTANt. decrease, and every time the process occurs there the result is but half as many cells as before. Practical Studies.—(a) Carefully scrape ofE (after moistening with a drop of alcohol) a little of the white, mouldy growth on lilac-leaves, known as LilaaBlight; mount it in water, adding a very little potas- sic hydrate. Some of the threads will show the formation of new cells (spores in this case) by fission. Other kinds of blights, as for example that on grass leaves or that common on the leaves of cherry- sprouts, furnish equally good examples. (See Fig. 79, p. 156) (b) Strip off carefully a bit of the epidermis (skin) of a young Live- for-ever leaf, and mount it in water. By careful examination some of the cells may be observed with very thin partition-walls formed across them. The new walls can be distinguished from the older ones by their thinness. (c) Mount a very small drop of yeast in water and observe in tbe yeast-plants that modification of fission wliich is called budding. Each yeast-plant is a minute oval cell; it first pushes out a little pro- trusion which becomes larger and larger, finally equalling the first. In the mean lime a parlition forms be- tween the two, which then separate from one another. ^Fig 4, a and ft.) (d) Grow some yeast for a few days under a bell-jar on a moist slab of plas- ter, a cut potato or carrot, or even a bit of moist brown paper. Upon ex- Tm. ^mining some such yeast it will be ingby diTision: n and 6 by bud- found that Some of the cells contain ; HfghlyyagnSld.'''"''''" several little new cells, formed by in- ternal cell-division. (Fig. 4, c and d.) (e) Make very thin cross-sections of young flower-buds so as to cut through the stamens. If the specimen is of the proper age, cer- tain cells maybe seen to have divided internally into four parts, each of wliich subsequently becomes a pollen-grain having a thick cell wall of its own. 18.
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Keywords: ., bookcentury1800, bookdecade1890, bookpublisher, booksubjectbotany
