Fluid preservation of organic material requires an initial fixing to prevent tissue breakdown and decomposition, commonly achieved using an aqueous solution of formaldehyde, or using ethanol. Post-fixation, specimens are frequently preserved in solutions of either 4% to 10% formalin, or 70-80% ethanol. Specialist fluids include Steedman’s method using propylene phenoxetol (PP), developed for use with small marine invertebrates. Steedman’s method was subsequently applied to a much wider range of zoological collections with varying reports of success. In more recent years the use of Steedman’s and PP has been questioned and it is now considered inappropriate for long-term storage. Despite this, an audit of the fluid-preserved collections at the Cole Museum of Zoology (REDCZ) showed that many specimens preserved in PP remain in good condition after almost twenty years.
A survey was distributed via the Natural History Collections and Natural Sciences Collections Association mailing lists to determine the variety of preservation fluids used in museum collections worldwide. Only half of the 35 respondents were aware of the recent recommendation to monitor or remove Steedman’s from their collections, and only two institutions had already followed this advice. Follow-up interviews with survey participants revealed wider systemic issues that prevent a deeper knowledge of fluid-preserved collections or ability to take appropriate action. These included a lack of financial resources, staffing gaps leading to a loss of institutional knowledge, a lack of suitable laboratory workspaces, and limited to no access to beneficial technology.
