Continuity mistake: In the final scene at the sheriff's office, Mitchum has his feet up on the table top, and the boot soles are clean. But after Wayne walks out, there is suddenly a spot on a boot sole. (This is visible in the video)
Continuity mistake: During the final showdown, when Jim Purvis is shot, he slumps onto the saloon porch face-up, with his left hand on his chest. But when Bart Jason is shot and falls right afterwards, Purvis is suddenly lying face-down on the porch.
Continuity mistake: As the sheriff returns from getting 'his evening bottle', the camera view from the rear shows his hat brim turned up. But when the view changes to the front, the brim is down. this change happens twice.
Continuity mistake: When Mississippi and Maudie return to the jail to deliver the news of Thornton's capture, and when Maudie begins to tell her part of the story, part of the veil she is wearing slides off her left shoulder. In the close-ups on the actress, the veil stays down, but in the far-off shots the veil is again draped over her shoulder.
Continuity mistake: When Cole throws the bucket of water on J.P. in the jail, J.P.'s shirt is soaked but his left arm is dry. His left arm changes back and forth from dry to wet.
Continuity mistake: In the cafe after Mississippi kills someone, Cole shoots the gun out of the hand of another gunslinger. The gun goes flying behind him past the piece of furniture along the wall. Later the gunslinger goes to pick up the gun which has appeared at his feet.
Continuity mistake: During the gun battle at the church, the bad guys are up in the bell tower shooting down on John Wayne's good guys. This is taking place in the middle of the night, but when the camera pans up towards a bad guy being shot in the tower, the sky behind him is obviously bright blue.
Continuity mistake: When JP is shot in the leg, it is his right leg that is shot and the younger doctor is tending to that particular leg. Then in the final scene, JP is using a crutch on his left side and using this right leg. He is favoring his left leg as if that is the injured one. (01:57:00)
Continuity mistake: Opening scene, JP confronts Cole in the wash room. Cole's collar is visible in the mirror. Sometimes it is nice and neat and sometimes messed up.
Answer: The prime ingredient was Ipecac, a nausea-inducing compound (still used today) which so inflames the stomach lining that it's impossible for the patient to hold anything down. Hot mustard in large doses has a similar effect. The other ingredients (croton oil, cayenne pepper, etc) acted as powerful laxatives, so the entire gastrointestinal tract is evacuated in short order. The gunpowder was a fantasy ingredient, no doubt, as gunpowder is known to cause gangrene of internal tissues.
Charles Austin Miller