In a medium saucepan melt the dark chocolate. Let it cool down and set aside. In medium mixer bowl combine egg whites. Beat on high speed until frothy. Gradually beat in sugar; continue beating until glossy. Add cream of tartar and beat again. Set aside. Blend in vanilla extract and dark chocolate. Fold into egg whites just until blended. Add chocolate chip and fold again carefully. Do not over mix. Drop by tablespoon on a baking sheet. Bake at 350 °F for 10 to 15 minutes.