Cruickshank, P.; Daniels, V.; King, J.; “A Great Lakes pouch: black-dyed skin with porcupine quillwork”, British Museum Technical Research Bulletin 3 (2009) 63-72PDF
A late eighteenth-century North American pouch (1937,0617.1) represents an important type of a black-dyed skin bag decorated with porcupine quillwork. The pouch was made by women of the Ojibwa or Ottawa people and was probably used in medicine ceremonies. It came to the British Museum in the mid-twentieth century and when first examined in detail in the 1970s had already deteriorated. The skin has degraded due to the presence of a black dye, although an early watercolour painting of the bag discovered in the 1990s illustrates how the bag once looked. Black dyes containing both iron and tannin are well known to increase the rate of deterioration of many organic substances and the pouch was found to contain 1.63% iron. Experiments with a series of brain-tanned skin samples stained with various iron-tannin solutions and artificially aged showed that the presence of iron accelerated the deterioration of the skin.
A conservation treatment carried out in the 1970s, which included consolidation with soluble nylon and backing with nylon net adhered with an early thermoplastic adhesive, was no longer succeeding in keeping the bag intact, and further conservation was carried out to protect the 75% of the bag that survives. As the pouch is of a rare type it was decided to infill the missing areas to make it more suitable for display. The use of adhesives was kept to a minimum and solvent-reactivated adhesives were chosen in preference to those reactivated by heat. No further chemical stabilization was attempted in this treatment.