General physiology of muscles and nerves / by I. Rosenthal.

  • Isidor Rosenthal
Date:
1883
Catalogue details

Licence: Public Domain Mark

Credit: General physiology of muscles and nerves / by I. Rosenthal. Source: Wellcome Collection.

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    ganism with variously formed parts is the result. Each part is originally a completely independent organism of equ^il value with all the others, and each has, therefore, been very aptly called an elementary organism. But together with the modification in the form, a change usually takes place in the qualities. Of the various qualities possessed by the protoplasm in its original form, some are lost, others are especially developed. A colony of uniform elementary organisms may be likened to a society in the lowest stage of civilisation, in which each member still personally performs all the tasks necessary to life ; but a composite organism, with variously developed and modified elementary organisms, may be likened to a modern state of which the various members perform very different tasks. The more highly developed plants and animals are of this sort. They originate from a number of elementary organisms—or cells, as they are also called—originally uniform; but these develop in very different ways—differentiate, as is technically said, and then acquire very different ap- pearance and purpose. In some the power of causing motion, which is originally common to all protoplasm, is especially developed; others effect sensation, which power was possibly or probably present even in the simple protoplasm. These will be fully discussed in the following chapters. But before doing this, a few words must be said as to one form of these modified cells, in which the power of generating motion is already de- veloped in a very noticeable degree, and serves partly for the independent movement of the cell-body, or of the animal of which the cell is a part; partly, when occurring in fixed bodies, to move foreign matter—that is, for the drawing in of food.
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