Aqueous gum-chloral slide mounting media: an historical review

Abstract

AbstractAn account is given of the development of aqueous gum-chloral mounting media used for mounting small arthropods on microscope slides. Berlese’s fluid is shown to have never been used by Berlese and other formulae are shown to have been randomly attributed to various authors, often incorrectly. Erroneous formulae and modifications to formulae have been followed by subsequent workers without reference to their origin. Details of the five formulae currently recommended in the literature are given and serious problems are shown to have been encountered with all of them by many workers. In many collections throughout the world gum-chloral slides are steadily deteriorating and specimens becoming irretrievably lost. Those workers advocating the use of gum-chloral aqueous media continue to propose alternative techniques in an attempt to overcome the problems they admit still occur. It is recommended that these media be used only for temporary mounts and never for specimens of taxonomic significance.