THE ECONOMIC IMPORTANCE OF ANIMALS 205 



tive. Already breeding of some fur-bearing animals has been 

 tried with success, and cheap substitutes for wild animal skins are 

 coming more and more into the markets. Black-fox breeding has 

 been tried successfully in Prince Edward Island, Canada, S2500 

 to $3000 being given for a single skin. Skunk, marten, and mink 

 are also being bred for the market. Game preserves in this 

 country and Canada are also helping to preserve our wild fur- 

 bearing animals. 



Animal Oils. — Whale oil, obtained from the fat or " blubber " 

 of whales, is used extensively for lubricating. Neat's-foot oil 

 comes from the feet of cattle and is also used in lubrication. 

 Tallow and lard, two fats from cattle, sheep, and pigs, have 

 so many well-known uses that comment is unnecessary. Cod- 

 liver oil is used medically and is well known. But it is not 

 so widely known that a fish called the menhaden or " moss 

 bunkers " of the Atlantic coast produces over 3,000,000 gal- 

 lons of oil every year and is being rapidly exterminated in 

 consequence. 



Hides, Horns, Hoofs, etc. — Leathers, from cattle, horses, 

 sheep, and goats, are used everywhere. Leather manufacture is 

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

 millions of dollars being invested in its manufacturing plants. 

 Horns and bones are utilized for making combs, buttons, handles 

 for brushes, etc. Glue is made from the animal matter in bones. 

 Ivory, obtained from elephant, walrus, and other tusks, 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. 



Protozoa. — The Protozoa have played an important part in rock 

 building. The chalk beds of Kansas and other chalk formations are 

 made up to a large extent of the tiny skeletons of Protozoa^ called 

 Foraminifera. Some limestone rocks are also composed in large part, of 

 such skeletons. The skeletons of some species are used to make a polish- 

 ing powder. 



