Reply to Comment on High-T sub c Scattering Rates.

This is a reply to a comment intended for Physical Review Letters. Markiewicz(1) suggests that optical measurements(2) on Ba sub 2 YCu sub 3 O sub (7-delta) may be interpreted in terms of carrier-carrier scattering. We agree that such scattering may play a role, but we question some of his analysis. We also caution that all of the optical absorption may not come from the mobile (in-plane) carriers and that a simple description of GAMMA may not apply. We agree with his remark that the substantial T-dependence of the normal conductivity introduces a complication in extracting the superconducting conductivity and energy gap 2 DELTA. This important feature of the high T sub c -materials is seldom apreciated. We believe our reflectivity criterion, R = 1 for omega2DELTA, is the best way to handle this complication.