344 MOTOR RESPONSES 



Oliphant (1938) made a much more extensive and thoroughly con- 

 trolled study of the effect of monovalent and bivalent cation salts on 

 ciliary reversal in ParameciutJi. 



The results obtained support the contentions of Mast and Nadler 

 (I926) that the monovalent salts induce reversal, whereas bivalent ca- 

 tion salts do not, and that the duration of the reversed action varies 

 with the kind and the concentration of the salts; but they do not support 

 their contentions as to the nature of this variation. The results show that 

 the effect of the salts is due primarily to the action of the cations, and 

 that the anions have little, if any, effect. They show that the order of 

 effectiveness of the cations is K>Li>Na>NH^, and that the duration 

 of their effect varies inversely with the temperature. 



Oliphant (1938) cites work which indicates that in Paramecium, 

 Amoeba, Actinos phaevmm , Spirogyra, root hair of Trianea, and eggs of 

 Arhacia, monovalent cations induce increase, and that bivalent cations 

 decrease the viscosity of the cytoplasm (Spek, 1921; Heilbrunn, 1923, 

 1931, Cholodnyj, 1923; Weber, 1924). He concludes that this indicates 

 that reversal in ciliary action is correlated with increase in viscosity of 

 the cytoplasm, and contends that this conclusion is supported by the fact 

 that "reversal in response to temperature occurs only at temperatures 

 almost immediately lethal," i.e., at temperatures which cause marked 

 increase in viscosity. He holds that the action of the cilia is controlled 

 by the neuromotor apparatus and that increase in viscosity produces im- 

 pulses in this structure which cause reversal in ciliary action, but he thinks 

 that changes in electric potential, in permeability, in the consistency of 

 the surface layer, or in the chemical composition of the receptors or 

 other structures in the organism may be involved. 



It is obvious from the above discussion that there is still much to 

 be learned concerning the processes involved in the responses of the 

 ciliates to chemicals. 



Literature Cited 



Alsup, Fred W. 1939. Relation between the responses of Amoeba proteus 

 to alternating electric current and sudden illumination. Physiol. Zool., 

 12: 85-95. 



Alverdes, F. 1923. Der Sondercharakter der von den Ciliaten gezeigten Gal- 

 vanotaxis. Pfiuger's Archiv ges. Physiol., 198: 513-42. 



