1. A technique for the quantitative cutaneous application of sulphur mustard vapour is described. The maximum rate of uptake of the agent vapour by shaved rat skin in vivo was estimated as 7-mu-g/cm2 per min. 2. The major route of excretion was through the kidneys: > 70% of the radioactivity of all doses was excreted in 3 days after either i.v. or i.p. injections of S-35-labelled sulphur mustard, but less (50-70% depending on dose) was excreted in the same time following cutaneous application. 3. This urinary excretion of S-35 had a half-life of 1-4 days, and the decreased proportion of the applied dose excreted following cutaneous application may be accounted for by retention of radioactivity in the skin. 4. The contribution of faecal excretion was greater following cutaneous application.
