Make the following “liquid-soap” mixture:
| Soft water | 2000 cc. |
| Strong ammonia | 150 cc. |
| Nitrate of potash (saltpetre) | 12 grams. |
| Hard soap | 75 grams. |
Heat these together till a homogeneous mixture is formed. Now immerse the bone or bones to be cleaned in a liquid composed of four parts water to one part of the above liquid-soap mixture. Boil forty minutes; pour off the liquid and renew it. Boil about half an hour longer; then remove soft parts with fingers, scalpel, and brush. The bones may be boiled as much longer in the mixture as is necessary to make the soft parts come away easily. If they are boiled too long, however, the epiphyses will separate from the bones. This is especially likely to occur in young skeletons, which must therefore not be boiled so long as the bones of an old cat.
Skeletons prepared in the following rough way are useful for many purposes. The entire body of the cat, or a single limb, is placed in the liquid-soap mixture (after partial removal of soft parts), and boiled till the muscles may be removed, but the ligaments, holding the bones together, remain. Clean thoroughly without removing the ligaments, and allow to dry. The bones are thus held together in their natural positions. Skeletons so prepared are not elegant, but are frequently useful.
Disarticulation of Skulls.
—The bones of the skull may be separated as follows: Clean the skull in the liquid-soap mixture, as above [described]. Then fill the cranial cavity with dry rice, beans, corn, or some other seeds that swell much on imbibition of water. Cork up the foramen magnum, and place the skull for twelve to twenty-four hours in water. The swelling of the grain will partially separate the bones at the sutures. The bones may then usually be separated completely by hand.
Entire skulls, and longitudinal sections, as represented in [Fig. 43], [p. 60], should be at hand.
Study of the Bones.
—The bones should be studied in the order in which they are described. No further special directions for their study are necessary.