Maintaining the collection of corrosion casts at Rīga Stradiņš University Anatomy Museum

RSU Anatomy museum holds a collection of around 200 corrosion casts that were made by anatomical preparator Jāzeps Poļikēvičs (1891-1938). Such specimens are made form casting vessels, ventricles or airways first by injecting organs and then macerating the tissue away. Allegedly Poļikēvičs had elaborated his own unique recipe for injecting the specimens, which has not been preserved to the present day. The objective of this study is to detect the potential components of the substance that was used for injections. This is crucial for maintaining this fragile collection in the future. The scientific publications form 1920s-1930s by the staff members of Anatomy institute of Medical Faculty of University of Latvia were analysed here. Additionally, samples from three different casts were analysed by infrared spectroscopy (FTIR-ATR and FTIR-transmission). Corrosion casting as a method was mentioned in two papers: 1) Gefässe der Lungen und Modus der Abzweigung der Bronchen (G. Backman, 1924) and 2) Lobierung und vascularisation der Leber der Säuger (L. Jeruma-Krastiņa, 1929). According to authors, corrosion casts were made by injecting Teichmann's mass (in Backman's work) or celluloid-acetone mass (in Jeruma-Krastiņa's work). In spectroscopy - two samples showed the presence of cellulose nitrate, so the injection mass most probably was celluloid, as expected. The third sample also showed the presence of cellulose nitrate on the outside and triolein in the interior. This may be a Poļikēvičs modification of the standard methods. Data retrieved form the literature and spectroscopic analysis supports the theory that at least part of the corrosion casts are made of celluloid. It is suggested to treat all types of museum corrosion casts as if they are composed of celluloid and try to limit the effects of the acidic breakdown products associated with these materials.