Silworm Gut Sutures The clear glass jar with a metal twistable red lid contains silkworm sutures, as indicated by the black ink writing on the white label. The label reads: "I.S. Sterilised silkworm gut, COARSE, 50 x 12" STRANDS in 2 1/2% carbolic solution," along with "International Sutures Ltd., Dublin, Eire." The carbolic solution is now missing, and the label appears very stained. 1925-1975