For crust, combine oats, sugar and butter, mixing until crumbly. Firmly press onto bottom and sides of a 23 cm pie plate. Place an 20 cm pie plate on top of the crust mixture; press down. Bake in preheated moderate oven (350 F.) about 8 minutes. Remove 20 cm pie plate; cool. For filling, dissolve gelatin in boiling water; stir in lemon juice and raspberries with juice. Chill until partially set. Beat egg whites until frothy. Gradually add sugar, a tablespoon at a time, beating constantly until stiff and glossy. Fold into gelatin mixture. Chill until mixture mounds when dropped from a spoon. Pour into pie shell. Chill several hours or until set.