ABSTRACT
Among the many extraordinary circumstances with which the phenomenon of ciliary motion is surrounded, it has not been the least, that we have scarcely been acquainted with a proper excitant of it. Whilst we were able to call the contractile substances into activity by mechanical, physical, and chemical agencies, the founders of the doctrine of ciliary motion, Purkinje and Valentin, could, as regards the cilia, find nothing but means to impede or destroy it. And the influence of mechanical agitation, the only means by which they had seen the failing vibration again become more vigorous, was doubted by Sharpey. Can it be said, therefore, that the ciliary substance is wholly and entirely different from the other contractile substances ?
A short time since, in examining a human trachea, I chanced to hit upon the discovery of a chemical excitant for the cilia. Upon the addition of a solution of potass to an object in which the ciliary movements, which were at first very lively, had begun to slacken, I noticed a renewal of the motion in every part, and that it lasted until the parts were destroyed by their solution in the caustic menstruum. I have since repeated this experiment under various conditions, and always with the same result. In a trachea from a human body, in which the ciliary movements had quite ceased in places, and was universally very faint, and in which the ciliated epithelium itself was readily destroyed upon the mere addition of water, I was still able to recal the phenomenon in great intensity, by the application of the potass-solution, although but for a short time. In better preserved and more recent mucous membrane, on the other hand, the revival of the motion could be maintained for a pretty considerable duration.
I have usually allowed a microscopic preparation, in which I had ascertained the existence of ciliary motion, to remain in contact with water until the motion ceased. Not unfrequently I was obliged to wait until large clear drops appeared on the surface of the cells between the cilia, which indicated the commencement of the splitting up of the contents. Under the prolonged action of the potass-solution, isolated cilia would first begin, here and there, to exhibit irregular, jerking movements. By degrees, more and more would begin to move, but in such a way that their movements were in opposite directions, and showed no correspondence either in direction or amount But gradually the phenomenon acquired more and more regularity, force, and uniformity, until at last the rapid, rhythmical, sweeping movement of whole series of cells would be seen to be restored.
That we have, in this case, to do with a chemical influence, is clear ; but that the entire phenomena of the motion cannot be the result merely of the corrosive action of the alkali, is evident from the perfect correspondence in the course of the phenomena with what is seen when the movements are spontaneous. It is only when the action of the potass is too powerful and rapid that the excitation is seen to be limited to a short, active agitation of the cilia, which is immediately followed by the solution of the substance ; and, in this case, it has very much the appearance as if it were the sudden swelling up of the substance in conjunction with the consequent undulation of the fluid which produced the motion. But even in such instances as this, it may be satisfactorily shown, by comparison with other similar minute corpuscles, that a moment of activity exists, in which the contractile substance produces a movement independent of the swelling up, and of the currents.
Soda acts in the same way as potass ; whilst the effect of ammonia, which at once causes chemical decomposition, is quite different. Nor have I been able to find any other substance having the same effect, although I would by no means preclude farther researches, my own inquiries having been too restricted to decide the matter. When the long list of chemical substances with which Purkinje and Valentin (Dephenomena gen. et fundam. motûs vibratorii continui,Vratisl. 1835, pp. 74—76) have unsuccessfully experimented, is surveyed, no great hopes certainly can be entertained ; and I consider myself particularly fortunate in having chanced at once to hit upon two substances overlooked by those careful observers. Nor indeed can they be justly blamed for this oversight, when it is considered that they had tried fifty different reagents, and each in six different degrees of concentration.
No further proof, perhaps, is requisite, to show, that the substance of the vibratile cilia, from their irritability, as proved in the above-described experiments, approximates the contractile substance of the muscles (syntonin, of Lehmann).
