Conservation of fluid preserved specimens

Selection of various educational specimens. (Image: TH Köln - CICS - Fabian Neisskenwirth)

This master thesis was dedicated in the development and implementation of a conservation concept for selected fluid preserved specimens of the Ruhr Museum Foundation. The aim was to treat a part of the collection of the now closed Fuhlrott Museum in Wuppertal, considering the material, technological and ethical aspects.

At a glance

Kategorie	Beschreibung
Student project	Development and implementation of a conservation concept on selected fluid preserved specimens of the Fuhlrott Collection at the Ruhr Museum Foundation.
Supervisors	Prof. Dr. Ester Simoes B. Ferreira
	Dipl.-Rest. (FH) M.A. Melanie Dropmann
Student	Fabian Neisskenwirth
CICS department	Natural Sciences
Project partners	Ruhr Museum, Essen
Duration	2019 - 2021

Picture gallery

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Schematic of a fluid preserved specimen in excellent condition, exemplified by an educational specimen from the Fuhlrott collection. (Image: TH Köln - CICS - Fabian Neisskenwirth)

„Raman-Bundle“ der Firma Ocean Insight (links oben) und Flüssigkeitspräparat mit Sonde (rechts oben). Raman Spektrum (unten) von Ethanol (blaue Line) im Vergleich zu dem der gemessenen Konservierungsflüssigkeiten im Gefäß (grüne Linie). Die charakteristischen Banden der Spektra sind identisch.

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„Raman-Bundle“ from Ocean Insight (top left) and fluid preserved specimen with probe (top right). Raman spectra (bottom) of ethanol (blue line) and the measured preservation fluid in the jar (green line) in comparison. The characteristic bands of the spectra are identical. (Image: TH Köln - CICS - Fabian Neisskenwirth)

Auszug aus einem Lehrmittelkatalog (rechts) von der Lehrmittelhandlung „Linnaea naturhist. Institut – Berlin“ aus dem Jahr 1892. (Bild: MfN, HBSB, ZM S II Linnaea). Das gleiche Flüssigkeitspräparat und direkte Referenz aus der Sammlung des Schulhistorischen Museum der Stadt Wuppertal (Mitte) und eins der behandelten Flüssigkeitspräparate aus der Sammlung Fuhlrott im Ruhr Museum (rechts). Dieser Vergleich hilft zur Datierung und dem Nachweis von Überarbeitungen.

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Excerpt from a catalog (right) from the teaching aids of the company "Linnaea naturhist. Institut - Berlin" from the year 1892 (Image: MfN, HBSB, ZM S II Linnaea). The same fluid preserved specimen and direct reference from the collection of the Schulhistorisches Museum der Stadt Wuppertal (center) and one of the treated specimens from the Fuhlrott collection in the Ruhr Museum (right). This comparison helped for dating and proofs reconditioning treatments made on the object. (Image: TH Köln - CICS - Fabian Neisskenwirth)

Hilfsmittel für das „minimal-invasive“ Auffüllen von verdunsteter Konservierungsflüssigkeit der Präparategläser. Kanüle (0,4 mm) mit übergestülptem PTFE-Schlauch (oben rechts); Kanüle und Spritze, um Flüssigkeit abzunehmen (unten links); Kanüle (1,2 mm) zur Führung eines dünnwandigen PTFE-Schlauchs (unten rechts). Auffüllprozess der ersten behandelten Flüssigkeitspräparate mit adaptiertem Infusionssystem (rechts).

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Tools for "minimally invasive" refilling of evaporated preservation fluid of the jars. Cannula (0.4 mm) with overlaid PTFE tube (top right); cannula and syringe to withdraw preservation fluid (bottom left); cannula (1.2 mm) to guide the PTFE tube (bottom right). Topping up procedure of the first treated fluid preserved specimens with adapted infusion system (right). (Image: TH Köln - CICS - Fabian Neisskenwirth)

Eins der konservierten Flüssigkeitspräparate vor der Behandlung (links) und nach dem Auffüllen und der Vernetzung der ergänzten Klebung (rechts). Das Lehrmittelpräparat wurde auf den Zeitraum 1888-1893 datiert, durch das Auffüllen blieb die ursprüngliche Konservierungsflüssigkeit ebenfalls erhalten.

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One of the fluids preserved specimens before treatment (left) and after filling and cross-linking of the infilled adhesive (right). The educational specimen was dated to 1888-1893, the topping up also preserved the original preservation fluid. (Image: TH Köln - CICS - Fabian Neisskenwirth)

Although fluid preserved specimens as part of natural history collections have a rather functional role as vouchers, those made for display purposes are characterized by how they are displayed.

During this project, a conservation concept for fluid preserved specimens from the natural history collection of the Ruhr Museum in Essen was developed to take into account the various material and non-material values of such collections. The heterogeneous state of preservation and the incomplete documentation of the preparations posed a particular challenge.

Material analysis was carried out as part of the documentation process. By means of Raman spectroscopy a noninvasive analysis of the preservation fluid could be performed through the glass. The use of a portable instrument provided by the company Ocean Insight enabled the analysis. Numerous comparisons with other collections of fluid preserved specimens within Germany were particularly helpful to characterise and document the educational specimens within the collection.

A conservation concept for the collection in its diversity, was developed. A decision-making model was created for this purpose combining different ethical considerations and technical requirements.

Finally, a small number of fluid preserved specimens which showed similar conservation problems was treated. However, it was quickly realized that there can be no single conservation concept, but that the conservation problem of each fluid preserved specimen must be treated singularly.