_Cooking._--After the skulls are placed in a tank they should be kept covered with cold water until collected in sufficient quantity for cooking. They should be thoroughly washed, as there is a large amount of clotted blood usually adhering to the skull, and if not well washed the grease derived from the cooking is discolored and injured. In connection with the washing, it is always well, when the vat is filled, to heat the water to a point about 90° F. and draw this water off. The vat is then filled with water sufficient to cover the skull and the steam turned on, the temperature raised to 200° F. The steam should be graduated so as to hold this temperature eight and one-half or nine hours, when the heads will be found to be cooked sufficiently. The steam is then shut off and the oil cooked from the heads is allowed to collect on the surface, after which it is skimmed and strained, and allowed to settle. It is then ready for tiercing. _Cleaning._--The skulls should be kept covered with water until ready for washing. This is done by passing through a reel screen arranged with a central hollow axle or a perforated pipe suspended in the top, used for spraying the revolving bones with a plentiful supply of warm water for cleansing them. _Jaw Bones._--Jaw bones should be handled the same as skulls, except that they should be cooked from nine to ten hours. The jaws are cracked at right angles to their length in order to open the bone for extracting all oil. _Drying._--The bones are now ready for drying. Dryers are mentioned subsequently. =Feet.=--The cattle feet are of prime importance owing to the value of the products resulting. In mentioning feet, we mean comprehensively the feet from knee to hoof, inclusive. _Washing Feet._--The feet upon being taken from the animal should be washed promptly, and all manure and refuse removed preferably through a revolving washer. _Cutting Sinews and Sawing Bones._--The sinews are removed from the feet, and the shin bones sawed out. The sawing of the bone is an important matter. The bone should be rigidly held and sawed by a sharp moving blade, the saw carriage moved against the tightly held foot. The set of saw should be such as to avoid a ragged edge. Saw should have high speed up to 1,200 r. p. m. and be filed with but little set. In moving the blade it should be done firmly and regularly--not jerky. The cutting should be done about midway through the “sponge” formation at end of bone so that the oil can be cooked clean. [Illustration: FIG. 61.--BONE SAW WITH IRON FRAME.] _Raw Shin Bones Cooling._--These bones should be kept in clear cold running water until the day’s cook is collected.