Strings (tennis) be more durable than many other types of strings due to its outstanding tension retention. This may help to offset the high initial cost. The use of a dense string pattern also generally improves the longevity of natural gut. Natural gut is produced by drying fibers extracted from a part of the cow intestine called the serous membrane, or serosa, which contains collagen designed to withstand the stretching and contraction of the intestine. It is this elasticity that makes the fibers useful for tennis string. Sheep intestines have also been used for racquet strings in the past. The first natural
Catgut suture anemia, and malnutrition. It also absorbed faster when used in the mouth and the vagina, due to the presence of microorganisms. Catgut has largely been replaced by synthetic absorbable polymers such as Vicryl and polydioxanone. It is not used at all for human surgery in some countries. In Europe and Japan, gut sutures have been banned due to concerns that they could transmit bovine spongiform encephalopathy (mad-cow disease), although the herds from which gut is harvested are certified BSE-free. Catgut suture is made by twisting together strands of purified collagen taken from the serosal or submucosal layer of the small