In a medium mixing bowl stir together flour, baking powder, sugar, cream of tartar, salt, and baking soda. Using a pastry blender, cut in lard (or shortening until mixture resembles coarse crumbs. Make a well in the center of dry mixture, then add buttermilk (or sour milk) all at once. Using a fork, stir (just until moistened).Turn the dough out onto a lightly floured surface. Quickly knead the dough by gently folding and pressing the dough for 10 or 12 strokes or until the dough is nearly smooth. Pat or lightly roll dough to 1/2 inch thickness. Cut dough with a floured 2 1/2 inch biscuit cutter, dipping the cutter into flour between cuts.Place biscuits on an ungreased baking sheet. Bake in a 450F oven for 10 to 12 minutes or until the biscuits are done. Remove biscuits from the baking sheet and serve hot.