Analysis of information sources in references of the Wikipedia article "羊腸線" in Chinese language version.
[T]here is no such thing as crude catgut or catgut unmanufactured. Catgut is a manufactured article and a finished product; the crude form are the intestines or guts of sheep or other animals.
Catgut sutures are made from the submucosal layer of the small intestine of sheep and the serosal layer of the small intestine of cattle.
