Pick over, wash, and drain currants. Put into a preserving kettle, adding a few at a time, and mash. Cook one hour, strain through double thickness of cheese cloth. Return to kettle, add sugar, heat to boiling point, and cook slowly twenty minutes. Add one quart raspberries when syrup again reaches boiling point, skim out raspberries, put in jar, and repeat until raspberries are used. Fill jars to overflowing with syrup, and screw on tops.