Use pear juice and water to make 1-1/2 cups liquid. Heat in sauce pan and dissolve gelatin. Stir in lemon juice. Cool to room temperature. Place pears in bottom of pyrex dish or gelatin mold. Blend raspberries into gelatin mixture. (If raspberries are frozen, this will set up very fast.) Pour mixture over pears, place in refrigerator. Use whipped cream when serving, if desired.