catgut

A tough cord prepared from the intestines of sheep (sometimes horse or ass, but never a cat). The intestine is cleaned, steeped in alkali, and sterilized by sulphur fumes. It has been used for musical instrument strings and surgical sutures (now replaced for the most part by synthetic fibres). Cat seems to be derived from kit ‘fiddle’.

The substance is used for the strings of harps, violins, and viols, as well as other stringed musical instruments, for hanging the weights of clocks, for bow-strings, and for suturing wounds in surgery. Catgut was also regularly used for stringing racquets in the past, though its use has diminished now with only one company, Babolat, continuing to use it in tennis raquets.

To prepare it, the intestines are cleaned, freed from fat, and steeped for some time in water, after which their external membrane is scraped off with a blunt knife. They are then steeped for some time in an alkaline lye, smoothed and equalized by drawing out, subjected to the antiseptic action of the fumes of burning sulphur, if necessary dyed, sorted into sizes, and twisted together into cords of various numbers of strands according to their uses.

Though catgut was in use for producing strings for many centuries and the Muslim physician al-Zahrawi utilized it in the 10th century, its use in the medical field became popular in the West only in the 19th century. Sutures made from catgut are readily absorbed by the human body and are consequently extensively used for internal stitches. Although synthetic alternatives are available, catgut sutures are still widely used in hospitals throughout the world.