ANIMAL PRODUCTS 355 



about 16,000 seals being killed in 1923. Otters, skunks, sables, 

 weasels, foxes, and minks are of considerable importance as fur 

 producers. Even cats are now used, the fur usually masquerading 

 under some other name. The fur of the beaver, one of the largest 

 of the rodents or gnawing mammals, is now difl&cult to procure, 

 but fur of considerable value is obtained from the chinchilla, musk- 

 rat, squirrel, and other rodents. The furs of the rabbit and nutria 

 are used in the manufacture of felt hats. The quills of the porcu- 

 pine (greatly developed and stiffened hairs) have a slight com- 

 mercial value. 



Animal Oils. — Whale oil, obtained from the ''blubber" of 

 whales, and formerly used for illumination, is now much used for 

 lubricating. Neat's-foot oil comes from the feet of cattle and is 

 also used in lubrication. Tallow from cattle and sheep, and lard 

 from hogs, have so many well-known uses that comment is 

 unnecessary. Cod-liver oil is used medically, and much oil is 

 obtained also from the menhaden of the Atlantic coast. 



Hides, Horns, Hoofs, etc. — Leather from cattle, horses, sheep, 

 and goats is used everywhere. Leather manufacture is one of 

 the great industries of the Eastern states, hundreds of millions of 

 dollars being invested in manufacturing plants. Horns and 

 bones are utilized for making combs, buttons, handles for brushes, 

 etc. Glue is made from the animal matter in bones, horns, and 

 hoofs. Ivory, obtained from the tusks of the elephant, walrus, 

 and other animals, forms a valuable commercial product. It is 

 largely used for knife handles, piano keys, combs, etc. 



Perfumes. — The musk deer, musk ox, and muskrat furnish a 

 valuable perfume called musk. Civet cats also give us a somewhat 

 similar perfume. Ambergris, a basis for delicate perfumes, comes 

 from the intestines of the sperm whale. 



Direct Uses of Protozoa. — The protozoa have played an impor- 

 tant part in rock building. The chalk beds of Kansas and other 

 places are made up to a large extent of the tiny skeletons of pro- 

 tozoa, called foraminifera. Some limestone rocks are also com- 

 posed in large part of such skeletons. The skeletons of some 

 species are used to make a polishing powder. 



Sponges. Coral. — The sponges of commerce have skeletons 

 composed of tough fibers of a material somewhat like that of a cow^s 



