. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. Reproduction of Paramcecium. — Somctimos a paramoecium may be found in the act of dividing by the process known as fission, to form two new cells, each of which contains half of the oiigi- nal cell. This is a method of asexual reproduc- tion. Frequently another method of reproduction may be observed. This is called conjugation and some- what resembles the same process in the thallo- phytes. Two cells of equal size attach themselves as shown below, complicated changes take place in the nucle
. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. Reproduction of Paramcecium. — Somctimos a paramoecium may be found in the act of dividing by the process known as fission, to form two new cells, each of which contains half of the oiigi- nal cell. This is a method of asexual reproduc- tion. Frequently another method of reproduction may be observed. This is called conjugation and some- what resembles the same process in the thallo- phytes. Two cells of equal size attach themselves as shown below, complicated changes take place in the nuclei of the two cells thus united, and after a short period of rest the two cells separate as two new individuals. These new animals appear to be rejuvenated as a result of conjugation, and may continue to reproduce asexU' ally by fission for a long period of time. Even- ually, howeve--, it seems necessary for the cells to conjugate in order to continue their existence. This stage of conjugation we believe in the plants to be a sexual stage. There seems every reason to believe that it is a like stage in the life history of the paramoecium. NAC. M/C. Paramoecium dividing by fission. Greatly magni- fied. M, mouth; MAC, macronucleus; MIC, micronucleus. (After Sedgwick and Wilson.). maQ Paramoecium conjugating. Greatly magnifietl. M, mouth ; Mic , micro- nucleus; Mac, macro- nucleus; CF., contrac- tile vacuole. (.\fter Sedgwick and Wilson.) Amoeba. — In order to understand more fully the life of a simple bit of protoplasm, let us take up the study of the amoeba, a type of the simplest form of life known, either plant or animal. Amoeba may be obtained from the dead leaves in the bottom of small pools, from the same source in fresh-water aquaria, from the roots of duckweed or other small water plants, or from green algae growing in quiet localities. No sure method of obtain- ing them can be given. Unlike the plant and animal cells we have examined, the amoeba has no fixed form. View
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