What does Jones v de Marchant establish?

A husband had, over time, given his wife some 18 beaver pelts with a view to them eventually being made into a fur coat. They were kept in cold storage until that time should come. However, at some point, the husband decided instead to have them made into a coat for his mistress. Four extra pelts had to be purchased to complete the coat, but it was mainly made out of the furs that he had given to his wife. the wife was determined to be the owner.