A new simple derivation is given of G. I. Taylor’s classic theory of solute transport in a straight capillary through which a liquid is flowing in a steady nonturbulent flow. The results derived are stronger, and an explicit representation is provided for the displacement of a solute molecule as the sum of a Brownian motion and the integral of an ergodic Markov process which is asymptotically a Brownian motion. Two curious identities involving zeros of the Bessel function of order one are obtained as a by-product.