88 



FACTORS AFFECTING CILIARY ACTIVITY 



of cilia of protozoa, notably the membranelles of Stentor (Kitching, 

 1957). An immediate decrease in frequency was found to occur 

 at pressures above about 1000 Ib/in^, and, although the beat per- 

 sisted up to 10,000 Ib/in^ in some cases, metachronal rhythm usually 

 broke down at about 4000 to 7000 Ib/in^. Investigations on 



♦ 4 - 



m 

 o 



u 



>« 

 u 



c 

 « 



xr 



M 



I. 



c 

 o 



o 



•D 



U 



o 



> 



> 

 o 



O) 



c 

 o 



X 



u 



« 

 o 



♦^ 



c 



* 

 a. 



-4 - 



•8 - 



-12 - 



-16 - 



-20 - 



2000 



4000 



6000 



Pressure in lb. /in 



Fig. 22. The immediate effects of increased hydrostatic 

 pressure on the metachronal wave velocity and the frequency 

 of beat of Stentor membranelles, 



Stentor by the present author (made using Dr. Kitching's 

 apparatus, which he generously made available to me) have 

 confirmed these findings on the effect of high pressure on the 

 frequency of ciliary beat in this organism (Fig. 22). This effect is 

 comparable with that found in Parameciujn by Ebbecke. There is 

 a slight but probably not significant increase in metachronal wave 

 velocity at pressures up to 5000 Ib/in^. In addition to the 



