SEM analysis of irregular fungal fox spots in an 1854 book: population dynamics and species identification

SEM micrographs of 111 “irregular fungal fox spots” in one book, published in 1854, were analysed to determine the morphology of the fungal structures; the hyphae, conidiophores and conidia, in the fungal spots throughout the book. The purpose of this study was to determine the number and identification of the different species, their distribution in the book and how the book paper was contaminated. The results showed that there were two fungal species randomly distributed on a page and on the pages throughout the book. This suggests the pages were contaminated from contaminated materials during paper making or book preparation. Thus, the irregular fungal fox spots are an inherent feature of the book, and are not caused by airborne contamination during use. Tests showed that the fungal structures in the spots were not viable. Species identification using SEM analysis of the conidiophore type and conidia ornamentation was undertaken. The two species are of the Aspergillus glauca group, probably two different Eurotium spp, which are facultative xerophylic species. Each species had unique hyphal characteristics, either mycofibrils or bacterial lytic holes, which suggested that the two species originated from two different environments. The species with mycofibrils was on top of the ink text and the hyphae with bacterial lytic holes was beneath the ink between paper fibres. This suggests two different times of contamination, one prior to printing and one at the time of printing or shortly after. The migration of the discolouration in the spots on facing pages and through 2–6 sequential pages shows that the discolouration developed after the book was completed. Comparison with another book published in 1785 showed similar results but different fungal species. The presence of minute mite-like animal's egg-shells, silk threads and faecal pellets suggests a complex ecosystem.