Arizona weekly citizen., 1885-08-01
THE YEAST PLANT.
Pecuiiarities of One of the Lowest Formi
 of Vegetable Life

ofNcgetable Life.
 Yeast is a substance which has long been known by the power which it pos sesses of exciting the process called fermentation Almost everybody is familiar with the fact that in the pro- cess of bread-making when yeast is added to mixture of flour and water it causes it to raise and that the raising is attended with the production of . sour smell and the formation of bubbles of gas which escape from the surface of the mixture in little putls. Now yeast has the power of awaken ing this activity only by virtue of it's being q living plant When some of it is added to the mixture of flour and water. the conditions of the growth of the plant are satisfied. it is able to get the kind of food on which it lives. and it is by it's very rapid growth and null tiplicstion th.t the fermenting process is caused.
 If s small drop of yeast be spread out into 6 thin layer and placed under the microscope. it will be found to con tain very many of these yeast plants. Judging from their appearance, no one unfamiliar with microscopic forms of life would ever suspect them to he plants. They ATe simply round or oval transparent bodies. lying single or associated Ia heaps or strings. They arc very small indeed. the largest be- ing only about one-thoussndth of an inch in diameter. EN- aniningEs single one of these plants, it will be seen to consist of a thin sac or bag. within which is con- tained a more fluid part. In the mid de of the fluid sometimes small, clear space appears, called the vaeuole. Nothing farther than this can be seen at a single examination, but if one of the bodies be watched for some time, a change in its appearance will be ob- served. It will be seen to give rise to a minute bud, which rapidly grows un- til it has assumed the size of the parent. It may then detach itself. and in its turn produce another bud. but usually the second bud begins to grow before the first has become detached, and m this way the strings and heaps are formed. Sometimes one of the plants multiplies itself in another way. It does not throw off bud. but the fluid matter inside the sac divides into four masses. and each of these having be- come surrounded with a sac of its own. the sac of the parent bursts Jpen and the four new plants are set free. Each of these rapidly attains its full size. and in it's turn. either by budding O. divi- sion. gives rise to others.
 These small bodies. being possessed of the power of growth, are living or ganisms. and the question arises whether they are animals or plants. That they belong to the plant king dom Is shown by their possession of two characters. In the first place, the outer covering. or sac, contains the substance cellulose, which Is one of the most characteristic con stituents of plants. Secondly. they possess the power of living upon inorganic matter; they are able to sepa- rate the four and water into the chem icsl elements which compose them, and out of these elements build up their own bodies. Animals. on the other hand. can live only upon organic mat ter, that is. upon other animals and plants. Yet there are two respects in which the yeast plant differs from all ordinary plants; it contains no green coloring matter, or chlOrOphyl, and il constantly throws Otf carbOnic acid gas and absoros oxygen. In these P..Tt Cu- lars it is at one with the animals; but as the two properties first mentioned are of a more fundamental nature than the latter, yeast is considered to belong to the plant kingdom.
 The vitality possessed by the yeast plant is very remarkable. It is able tC keep alive in dry state for very long time. probably many years The con ditions required for it's growth are heat, moisture, and the presence of sugar. or it's chemical equivalent As soon as these conditions are satisfied, it grows and multiplies with great rapidity. so that a small quantity will in a short time produce an amount many thou sands of times as great in bulk. It is said, on good authority, that under favorable circumstances one plant will produce one million in one day. The growth of the plant is attended with the formation of two bodies, ear bopic acid and alcohol These sub, stances are formed at the expense Oi the sugar contained in the matter iT which the yeast is placed. la the rsis ing of bread, the bubbles of gas formed are csrbonic acid gas, and the soul smell generated is due to the fOrma ton of alcohol In brewing, the graiI is first caused to sprout, this changing its starch into sugar. The groWins process is then interfered with, an, yeast. the plant now being able t0 sub sist on the sugar, is added. and fer mentstion ensues.
 The yeast plant Is one of the Vcrl lowest forms of vegetable life. Lik' the lowest animals, 1t consists Of . single simple cell. The material O which the cell is made. except as tO thu cellulose sac. is just the same as ina of the lowest animals, viz, ProtOplasm m The yeast plant is like the lower ani mals, too, in the manner in which ! reproduces itself-by fssion and bl gemmation or budding. But it show its resemblance to the higher member of the kingdom to which It belongS II that it is 2 fixed organism, not able t' move about from place tO place Country Gentleman.
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