Response in the living and non-living / by Jagadis Chunder Bose.

  • Jagadish Chandra Bose
Date:
1902
Catalogue details

Licence: Public Domain Mark

Credit: Response in the living and non-living / by Jagadis Chunder Bose. Source: Wellcome Collection.

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    disturbance, we apply salt solution, they again contract, in the same way as before. Similar effects are produced by sudden illumination, or by rise of temperature, or by electric shock. A living substance may thus be put into an excitatory state by either mechanical, chemical, thermal, electrical, or light stimulus. Not only does the point stimulated show the effect of stimulus, but that effect may sometimes be conducted even to a con¬ siderable distance. This1 power of conducting stimulus, though common to all living substances, is present in very different degrees. While in some forms of animal tissue irritation spreads, at a very slow rate, only to points in close neighbourhood, in other forms, as for example in nerves, conduction is very rapid and reaches far. The visible mode of response by change of form may perhaps be best studied in a piece of muscle. When this is pinched, or an electrical shock is sent through it, it becomes shorter and broader. A responsive twitch is thus produced. The excitatory state then dis¬ appears, and the muscle is seen to relax into its normal form. Mechanical lever recorder.—In the case of contrac¬ tion of muscle, the effect is very quick, the twitch takes place in too short a time for detailed observation by ordinary means. A myographic apparatus is there¬ fore used, by means of which the changes in the muscle are self-recorded. Thus we obtain a history of its change and recovery from the change. The muscle is •connected to one end of a writing lever. When the muscle contracts, the tracing point is pulled up in one
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