Reliability of the results presented in the paper in question is discussed. Arguments against the suggested reasons of existence of the observed 'saturation value' of hydrogen (H) concentration in the Pd81Pt19-H solid are given. Also a majority of sets of the diffusion coefficient of H vs. electrode potential is questioned, as they were derived: (i) from experiments performed at large gradients of H concentration, and (ii) under assumption that also in a membrane specimen the transport of H is Fickian. The above is supplemented by suggestions on proper experimental techniques and methods for obtaining reliable results. (c) 2006 Elsevier B.V. All rights reserved.