  The NMR relaxation data on Sr_2CuO_3 [Phys. Rev. Lett. 76, 4612 (1996)] are
reexamined and compared with the analytic theory of the dynamic susceptibility
in the S=1/2 antiferromagnetic Heisenberg chain including multiplicative
logarithmic corrections [Phys. Rev. Lett. 78, 539 (1997); cond-mat/9610015].
Comparisons of the spin-lattice and the gaussian spin-echo decay rates (1/T_1
and 1/T_{2G}) and their ratio all show good quantitative agreement. Our results
demonstrate the importance of the logarithmic corrections in the analysis of
experimental data for quasi-1D systems and indicate that the dynamics of
Sr_2CuO_3 is well described by a S=1/2 one-dimensional Heisenberg model with a
nearest neighbor exchange.
