It is impossible to give all the combinations of meats and vegetables that are suitable to casserole use, but, as a general rule, it may be stated that the heavier vegetables of pronounced flavor, such as tomatoes, onions, carrots, turnips, parsnips and the like may be used with such heavy meats as beef, pork and ham, while the lighter vegetables - peas, asparagus, string beans and corn - are better suited to meats like chicken, pigeons, lamb, veal and guinea-fowl. This does not mean that onions, tomatoes and green peppers should be entirely omitted from the casseroles of lighter meats, but that they should be used more sparingly, only to assist in creating the fillip which will whet the appetite.