2 1/2 cups flour
1 tsp baking soda
1/2 tsp salt (omit if salt pork is used)
1 tsp mixed allspice
1/2 cup butter or 1 cup suet (cut fine) or 1/2 salt pork (cut fine)
1 cup molasses
1 cup milk or water
1 cup raisins
1 cup currants (optional)
1/3 cup peel (optional)
Sift flour, soda, salt, and spice. Add molasses and milk (or water). Add fruit coated with flour and butter. Mix well. Steam for 2 1/2 hours boiling constantly. Serve with a sauce.

What is mixed spice? Is there something called mixed spice?
Maybe they mean Allspice?