_Sterilizing._--During the last quarter of the century, which has witnessed the growth of the wonderful science of bacteriology, a class of devices known as sterilizers has come into existence, whose primary function is to kill the germs of decay by heat. This has had in the canning industry an important commercial application. An example is found in the patent to Shriver, No. 149,256, March 31, 1874. In some of these devices the receptacles containing the food stuffs are in large numbers placed within the heating chamber, and by devices operated from the outside the cans or bottles are opened and shut while within the steam filled chamber. A late illustration is found in patent to Popp _et al._, 524,649, August 14, 1894. _Butchering and Dressing Meats._--Chicago is the leading city of the world in this industry, and Armour & Co. the largest packers. In the year ending April 1, 1891, they killed and dressed 1,714,000 hogs, 712,000 cattle, and 413,000 sheep. They had 7,900 employees, and 2,250 refrigerating cars were employed for the transportation of their products. The ground area covered by their buildings was fifty acres, giving a floor area of 140 acres, a chill room and cold storage area of forty acres, and a storage capacity of 130,000 tons. In addition to its meat packing business the firm has separate glue works, with buildings covering fifteen acres, where 600 hands are employed, their production in 1890 being 7,000,000 pounds of glue, and 9,500 tons of fertilizer. Since 1891 this great business has increased until to-day it is said that the army of workmen employed is greater than that of Xenophon, that the firm pays out in wages alone, half a million dollars every month, that four thousand cars are required to carry the products of their factory, and whose business amounts to the enormous sum of one hundred million dollars annually. [Illustration: FIG. 170.--KILLING AND DRESSING PORK.]