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,
Geophone (musical instrument) performance in New York City). Messiaen's wife, Yvonne Loriod, commented that when she and the composer first collected the new instrument from the maker in her car it made a "splendid crescendo" whenever they went round a corner. Messiaen also included the instrument in his only opera, "Saint François d'Assise", which was first performed in Paris 1983. Other works that use the geophone include "Asyla" by Thomas Adès, "…towards a Pure Land" by Jonathan Harvey, and the operas "The Sacrifice" by James MacMillan and "Dark Sisters" by Nico Muhly. Geophone (musical instrument) The geophone is a percussion instrument, invented by