Coarsely chop the venison and then the pork and fat, keeping the venison separate. In a bowl, combine the pork and fat and 1 tablespoon of the salt. Using a meat grinder or food processor, process the pork mixture to the size of lentils, then set aside. In another bowl, mix the venison with 2 tablespoons of salt and the pepper, garlic, onion, ginger, and juniper berries. Process two-thirds of this mixture in the meat grinder or food processor to the size of lentils, and set aside. Combine the remaining one-third with half of the pork mixture, along with the egg whites and arrowroot, and pulverize in a food processor until it forms a smooth paste. Stir all the elements together, then form a small patty and fry it to check the seasonings. Stuff the casings, then twist them at 6-inch intervals to form sausage links. Using a skewer, puncture each link 4 or 5 times. To cook, poach the sausages in barely simmering water for 15 to 20 minutes, or until a meat thermometer reads 150 degrees. You can freeze them at this point. Just prior to eating, grill them over a medium fire until heated through and nicely browned. You may also skip the poaching and grill the sausages immediately after stuffing for about 15 minutes over a medium-low fire.