Carl Linnaeus, The Lapland Journey, translated by Peter Graves (Edinburgh: Lockharton Press, 1995), p. 112.
Jokkmokk, 04/07/1732, ¶561:
Some people make rennet by removing the rennet stomachs from reindeer calves that die in winter. Milk is then poured into them and they are hung up to dry ready for use.