278 C. J. BROKAW 



Is is entering through the broken end, or will the system work 

 equally well if it is not bounded by any permeability barrier? Fi- 

 nally, the ultimate question: Are there any functional reasons for 

 the uniformity of flagellar ultrastructure? 



These and other questions remain for the future. So far, promising 

 results have been obtained by applying two quantitative measures, 

 frequency of beat and rate of dephosphorylation of ATP, to the 

 isolated flagella. Hopefully it will be possible to measure other 

 parameters and eventually to obtain a more nearly complete model 

 of the rhythmic contractile process in flagella. 



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