BRISTLE. The stiff hair of swine. Its forked tips, resiliency, and minutely ridged surface have made it a basic material in brush manufacture for many centuries. It is produced and pre pared chiefly in China, the Soviet Union, Japan, Poland, India, Germany, and France. The increased use of brushes has made bristle an important article of commerce. The United States im ports annually an average of about 4,000,000lbs., 1938 imports being 3,200,000lbs. valued at $5,5oo,000.