Handbook of physiology / by W.D. Halliburton.

  • Halliburton, W. D. (William Dobinson), 1860-1931.
Date:
1919
Catalogue details

Licence: Public Domain Mark

Credit: Handbook of physiology / by W.D. Halliburton. Source: Wellcome Collection.

    49/974 (page 25)
    Ciliary Motion. Ciliary motion reminds one of amoeboid movement, but it is much more rapid, and more orderly. It consists of a rhythmical movement of the cilia, a bending over, followed by a lessening of the curvature, repeated with great frequency. When living ciliated epithelium, e.g., from the gill of a mussel, or from the mouth of the frog, is examined under the microscope in a drop of 0 9 per cent, solution of common salt {normal saline solution), the cilia are seen to be in constant rapid motion, each cilium being fixed at one end, and swinging or lashing to and fro. The general impression given to the eye of the observer is very similar to that produced by waves in a field of corn, or swiftly running and rippling water, and the result of their movement is to produce a continuous current in a definite direction, and this direction is the same on the same surface, being usually in the case of a cavity towards the external orifice. There is not only rhythmicality in the movement of a single cilium, but each acts in harmony with its fellows in the same cell, and on neighbouring cells. The uses of cilia can from the above be almost guessed; in the respiratory passages they create a current of mucus with entangled dust towards the throat; in the oviduct they assist the ovum on its way to the uterus; in the gullet of the frog they act downwards and assist swallowing; in the ciliated protozoa they are locomotive organs. Over the gills of marine animals they keep up a fresh supply of water, and in the case of the rotifers, which are fixed animals, the current of water brings food to the mouth. Ciliary motion is independent of the will, and of the influence of the nervous system. It may continue for many hours after death or removal from the body, provided the portion of tissue under examination be kept moist. Its independence of the nervous system is shown also in its occurrence in the lowest invertebrate animals, which are unprovided with anything analogous to a nervous system. The vapour of ether or chloroform and carbon dioxide arrest the motion, but it is renewed on the discontinuance of the application. The movement ceases when the cilia are deprived of oxygen, although it may continue for a time in the absence of free oxygen, but is revived on the admission of this gas. The contact of various sub¬ stances, e.g., bile, strong acids, and alkalis, will stop the motion altogether; but this depends on destruction of the delicate substance of which the cilia are composed. Temperatures above 453 C. and near 0° C. stop the movement, whereas moderate heat and dilute alkalis are favourable to the action, and revive the movement after temporary cessation. The exact explanation of ciliary movement is not known ;