Outlines of evolutionary biology / by Arthur Dendy.

  • Arthur Dendy
Date:
[1912]
Catalogue details

Licence: Public Domain Mark

Credit: Outlines of evolutionary biology / by Arthur Dendy. Source: Wellcome Collection.

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    adaptation to its environment, and whose action consists in continual self-adjustment to changes in that environment. What we call the life of the organism consists of the sum total of all the activities which it thus exhibits. The question at once arises: How, then, does a living organism differ from a mere man-made machine ? and this question is one which it is by no means easy to answer. An organism, however, is not merely a piece of apparatus which has the power of maintaining itself for a longer or shorter period in a state of equilibrium with its environment and thereby preserving itself from destruction, for it also has the power of reproducing its kind by a process of self- multiplication. In the case of an artificial machine, where there is little or no automatic adjustment, the forces of the environ¬ ment very soon get the upper hand ; the metal work becomes corroded by oxidation, or worn away by friction, and presently the whole affair comes to a standstill. Oxidation and friction, and innumerable other chemical and physical agencies also tend to destroy the machinery of the living body, but for a longer or shorter period they are held in check by automatic processes of repair and renewal, and when the inevitable end does come it is usually not until the organism has produced at least enough off¬ spring to take its place in the struggle for existence. One of the most brilliant writers of the nineteenth century, Samuel Butler, has indulged in the somewhat fantastic sugges¬ tion that some day the construction of machines might be so perfected that they also would be able to reproduce their kind, and the little steam-engines would be seen playing about the door of the engine shed. It certainly does not seem possible that machines will ever multiply in this way, but should they do so, and should they at the same time be able to feed and grow, it is difficult to see why they should not be as much entitled to be called living organisms as any of the plants and animals which inhabit the earth to-day. They would, however, still be totally different from plants and animals both in structure and composition. One of the most remarkable and characteristic features of the living things which inhabit this earth is that they are all com¬ posed of very similar materials, which are very different in their nature from any which we should be likely to choose in the construction of a machine. In making an engine we select those substances which seem best calculated to resist the destructive B 2
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