122 



The Mechanism of Ciliary Movement. II. — The Effect of Ions 

 on the Cell Membrane. 



By J. Gray, M.A., Fellow of King's College, Cambridge, and Balfour 

 Student in the University of Cambridge. 



(Communicated by Prof. J. S. Gardiner, .F.E.S. Received October 7, 1921.) 



In 1906 B. S. Lillie (7) published an account of the effects of various 

 pure sodium salts upon the ciliated epithelium of Mytilus edulis. He found 

 that the ions could be arranged in the following order of " toxicity," 



CI' < ¥0 3 ' < Br' < I' < SCN'. 



Lillie also referred to the effect which various anions have upon the 

 amount of water taken up by the cells from their external medium, and 

 arranged the ions in the following order of efficiency in causing an absorption 

 of water by the cells. 



CH 3 COO' < G'l' < N0 3 ' < CIO3' < Br' <F < SCJSP < Br0 3 ' < OH'. 



These results form the basis of the following statements found in recent 

 text-books, viz., Hober (6) and Bechhold (1) : — 



(i) That the above series represents the effect of anions on ciliary 

 movement. 



(ii) That the order in which anions affect ciliary movement is the reverse 

 of that in which they affect muscular movement. 



One of the objects of the present communication is to consider whether 

 these important statements are justified. 



It has already been shown (Gray (3)), that if the ciliated epithelium of 

 Mytilus edulis is placed in a solution containing NaCl, KC1, CaCh> and 

 MgChj, the whole tissue remains normal and in activity for a very prolonged 

 period. If we wish, therefore, to determine what specific role, if any, is 

 being played by the chlorine ion, it is necessary to replace this ion in the 

 above solution by other anions. It is not permissible to use a solution 

 which does not contain either K' ; Ca", or Mg", nor is it permissible to 

 ignore the hydrogen ion concentrations of any experimental solution 

 (Gray (3)). 



In the experiments tabulated in Table I, each solution contained the same 

 molecular concentration of cations, and the hydrogen ion concentration was 

 kept well within the limits to which the tissue is indifferent. 



