Skin lesions in the fingertips may sometimes bleed and cause pain. He would bleed from the navel and his blood was slow to clot. The wound does not bleed and is almost invisible. The shrapnel tears open Leer's hip, causing him to bleed to death quickly. Others had their bowels punctured, causing them to bleed profusely. Without timely treatment, these new blood vessels can bleed, cloud vision, and destroy the retina. These may bleed, leading to blood in the stool. This area may also bleed and blister and can eventually lead to tissue necrosis. He bites his nails until they bleed. Thomas begins to bleed from the eyes and convulse violently. I bleed continuously and do not become pure. In some cases, ulcers can bleed and, rarely, patients experience fever. They are no longer decapitated or dismembered, instead they just bleed and weaken. The lesions progress to thick crusts which may bleed. Greek anatomist Erasistratus observed that arteries that were cut during life bleed.