Scoop out passionfruit.  Make a syrup by boiling sugar and water together, stir in acid.  Pour syrup on to fruit.  Allow to stand 1/2 hr.; strain and bottle to overflow.  Stand bottle in saucepan of water.  Bring to boil to sterilize.  Boil 15 mins.  Cork and seal.

This syrup will not keep for a length of time.

From

The Housewife's cookery book and shopping guide. 5th edition.