Further evidence in support of the authenticity of microorganisms believed to have survived for 5300 years.

It has been questioned whether the microorganisms isolated from hay, which the ice-man had used for padding his boots, were authentic. The arguments in favour of, and those brought forward against, the authenticity are discussed. Based upon additional circumstantial evidence we maintain our view that the microbial strains isolated from the grass samples are more likely to be of ancient origin than to have been derived from secondary contamination.