To the Editor: Regarding the letter in the April 27 issue of the Journal by Gajdusek et al. we have additional information, given below, regarding the resistance of the causal agents of conditions like scrapie and Creutzfeldt-Jakob disease to decontamination. Our results come from studies with scrapie, which provides the best and most practicable model. The limited knowledge of the properties of the human-disease agents means that, until more information is available, it is necessary and reasonable to regard known decontamination requirements for scrapie as appropriate for the human agents.Glutaraldehyde is used as a fixative at concentrations up to . . .