Peel and seed lychees. Squeeze lychees through 2 thicknesses of cheesecloth to obtain 1 cup juice. Sprinkle gelatin over cold water and let stand 5 minutes. Scald milk, add soaked gelatin, and stir until thoroughly dissolved. Add sugar, mixing well.
Cool. Add milk and half and half. Stir in lychee and lemon juice. Freeze in ice cream freezer.
