Complex sentence: A shriek is heard, and the annoyed reptile is soon found to have injected its venom into the murderous physician; when Holmes and Watson enter the death scene, the swamp adder has wound its body around the head of its victim in triumph.
Split into simpler sentences: A shriek is heard, and the annoyed reptile is soon found to have injected its venom into the murderous physician. When Holmes and Watson enter the death scene, the swamp adder has wound its body around the head of its victim in triumph.