. An introduction to zoology, with directions for practical work (invertebrates). 6 /NTJ^ODUCT/ON TO ZOOLOGY. Fit!. 1.—Amoeha 2^i'oteiis. x 300. 7i//, Niieleuy : ps, pseudopodium ; on. var., contractile vacuole ; /. car, food vacuoles. Structure When so magnified, it is seen as a round, or more or less irregular, body, of a semi-fluid con- sistencj^, the greater part of it being finely granular, whilst round the margin is a clear ' ' " " non-granular border. It is colourless or slightly greyish in tinge, but within the trans- parent body can be seen vaiious opaque food particles whic
. An introduction to zoology, with directions for practical work (invertebrates). 6 /NTJ^ODUCT/ON TO ZOOLOGY. Fit!. 1.—Amoeha 2^i'oteiis. x 300. 7i//, Niieleuy : ps, pseudopodium ; on. var., contractile vacuole ; /. car, food vacuoles. Structure When so magnified, it is seen as a round, or more or less irregular, body, of a semi-fluid con- sistencj^, the greater part of it being finely granular, whilst round the margin is a clear ' ' " " non-granular border. It is colourless or slightly greyish in tinge, but within the trans- parent body can be seen vaiious opaque food particles which have been absorbed. The body is continually changing its shape, sending out a process now in one direction, now in another, or, if touched, with- drawing all its processes, and becoming round in outline. The substance of which this body is formed is that Protoplasm, of which Professor Huxley wrote as "The Physi- cal Basis of Life";^ for it is the substance which is present in ((// living things, be they plant or animal, and which, so far as we know, alone renders possible the phenomenon which we call physical life. On carefully examining this protoplasmic bod}', two struc- tures can usually be readily detected, embedded within it. There is a small, oval or round, darker mass known as the nucleus of the protoplasm. In chemical composition, this is very similar to the rest of the living protoplasm, but it is denser, and it performs special important functions within the cell, controlling apparently the nutritive and reproductive processes. Then, after a little search, a clear round space can also be seen, which will disappear suddenljr, and then slowly form again, thus gaining the name of the contractile vacuole. When visible, the space is filled with a watery fluid ; when the vacuole contracts, this fluid is driven in radiating streams out of the protoplasmic body. Such a mass of living protoplasm with its nucleus is known as a cell, and Amoeba is therefore said to
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