Kirkes' handbook of physiology. / By W. Morrant Baker and Vincent Dormer Harris.

  • William Senhouse Kirkes
Date:
1888
Catalogue details

Licence: Public Domain Mark

Credit: Kirkes' handbook of physiology. / By W. Morrant Baker and Vincent Dormer Harris. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

    53/912 page 29
    When living ciliated epithelium, e.g., from the gill of a mussel, or oyster, or from the mouth of the frog, or from a scraping from a polypus from the human nose, is examined under the microscope, 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 im'ariably the same on the same surfece, being always, in the case of a cavity, towards its external orifice. Ciliary Motion.—Ciliary, which is closely allied to amoeboid and muscular motion, is alike independent of the will, of the direct influence of the nervous system, and of muscular contraction. It continues for several hours after death or removal from the bod}', provided the portion of tissue under examination be kept moist. Its independence of the nervous system is shown also in its occuiTence in the lowest invertebrate auimals apparently unprovided M'ith anything analogous to a nervous system, in its persistence in animals killed by prussic acid, by nai'cotic or other poisons, and after the direct application of narcotics, such as morphia, opium, and belladonna, to the ciliary surface, or of electricity through it. The vapour of chloroform arrests the motion; but it is renewed on the discontinuance of the application (Lister). The movement ceases when the cilia are deprived of oxygen, but is revived on the admission of this gas. Carbonic acid stops the movement. The contact of various substances, e.g., bile, strong acids, and alkalies, will stop the motion altogether; but this seems to depend chiefly on destruc- tion of the delicate substance of which the cilia are composed. Temperatures above 45° C, and below 0° C, stop the movement, l)ut moderate heat and dilute alkalies are favo\u-ablc to the action and revive the movement after temporary cessation. As a special sub-division of ciliary action may be mentioned the motion of spermatozoa, which may be regarded as cells witli a single cilium. B. Transitional Epithelium.—This term has been applied to cells, which are neither arranged in a single layer, as is the ca.sc with simple epithelium, nor yet in many su])erim])osed strata as in laniiriiited ; in other words, it is employed when epithelial cells arc found in two, three, or four superimposed layers. The upj)cr layer may be cither columnar, ciliated, or squamous.
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