We have studied one of the rare occasions when the same piece of solar wind plasma passed both Helios 1 (at 0.507 AU) and Helios 2 (at 0.72 AU). Our particular example occurred in the middle of a fairly smooth and typical high-speed stream. We find clear indications that the ion behavior during this transit did not conserve the partirlces adiabatic vineriants and that some heating is required for the proton and alpha perpendicular temperature. The situation regarding the parallel temperature is less clear. The decreasing alpha-proton differential speed does not appear to release very much free energy owing to a natural ''adiabatic'' cooling process. A very strong radial dependence of the electromagnetic energy flux, along with other factors, suggests the possibility of strong dissipation of Alfvenic fluctuations. Our conclusions are weakened somewhat by the many sources of inaccuracy that we have found and that seem unavoidable in a study of this kind.