There are from forty to fifty million cattle raised in the United States, and an equal amount of sheep. The number of hogs raised has diminished somewhat in the past few years, but from 1889 to 1892 more than fifty million were maintained. The process of slaughtering and dressing pork, as practiced to-day, is a continuous one, and is well illustrated in Fig. 170, in 13 operations. The animals are driven into a catching pen at 1, where they are strung up by one leg, and secured to a traveling pulley on an overhead rail. At 2 the animal is instantly killed by a knife thrust that reaches the heart; at 3 he is dumped into a vat of scalding water, kept hot by steam pipes, where the hair is loosened (see detail view Fig. 171). A series of oscillating curved arms, shaped like a horse hay-rake, dips the carcass out of the scalding vat and deposits it upon the table 4 (Fig. 170), where it is attached to an endless cable that drags it through a scraping machine at 5. This takes off the hair, as shown in detail view Fig. 172. At 6 (Fig. 170) the remnants of hair are removed by hand, and at 7 the skin is washed clean. At 8 the carcass is inspected, and the throat cut across; at 9 the entrails are removed; at 10 the leaf lard is taken out; at 11 the heads are severed and tongues removed; at 12 the carcass is split into halves, and at 13 the sections are ready to be run into the cooling room. [Illustration: FIG. 171.--SCALDING TO LOOSEN THE HAIR.] [Illustration: FIG. 172.--SCRAPING OFF THE HAIR BY MACHINERY.] From 10 to 15 minutes only are required to convert the living animal into dressed pork. Every part of the animal is utilized. The lungs, heart, liver and trimmings go to the sausage department. The feet are pickled or converted into glue. The intestines are stripped and cleaned for sausage casings. The soft parts of the head are made into so-called cheese, and the fat is rendered into lard. The finer quality of bristles goes to the brushmakers, and the balance is used by upholsterers for mixing with horse hair. The blood is largely used for making albumen for photographic uses, as well as in sugar refining, for meat extracts, and for fertilizers. The bones are ground for fertilizer, and even the tank waters are concentrated and used for the same purpose.