Catgut down to the desired diameter using a centerless grinder. After drying and polishing, workers bleach and disinfect the strings using sulfur dioxide, dye them if necessary, and sort them into sizes. Catgut sutures are normally treated with a chromium salt solution to resist body enzymes, to slow the absorption process, and are called catgut chromic sutures—whereas untreated catgut sutures are called catgut plain sutures. Catgut Catgut is a type of cord that is prepared from the natural fibre found in the walls of animal intestines. Catgut makers usually use sheep or goat intestines, but occasionally use the intestines of cattle,
Catgut as withstanding high tension within low alto, tenor, and high-bass ranges. Many acoustic guitarists moved away from gut strings in the early 1900s when the C. F. Martin & Company introduced steel strings, which gave greater volume to the guitar. "The demand for steel came from ensemble players, who couldn't make themselves heard clearly without it." Within a few years the majority of Martin guitars were made with steel strings to accommodate the demand. After World War II, most classical and flamenco guitarists switched from catgut to the new nylon strings for their greater smoothness, durability, and stability of intonation.