The Blood Test The Thing (1982)

The blood-test sequence in beats 32–34 is the post-midpoint approach in full execution. MacReady, having watched Norris's severed head walk under a desk on insect legs, reasons in the rec room that every piece of the Thing acts to save itself, and that a sample of its blood pulled from the host and threatened with a hot needle will try to crawl away. He calls for petri dishes and a length of copper wire heated red on a steel rod. Windows and Palmer tie the surviving men to the long couch in the rec room. Clark refuses to be tied; MacReady warns him off and shoots him in the head. The test runs. Windows passes; MacReady passes; Doc Copper's blood (drawn from his corpse) passes; Clark's blood passes, meaning the shooting was the killing of a man. Palmer's blood squeals and leaps from the dish; Palmer's body splits open in his bonds; he is torched in the doorway. Garry, Nauls and Childs all pass.^{b32 b33 b34}

The test is the post-midpoint approach made operational

The test is the most-cited concrete example of the substitution of evidence for trust that the film argues for after the midpoint. Doc Copper's serum test in beat 20 — destroyed in beat 21 before it could run — was the institutional version of the same logic; the post-midpoint approach is the same logic in a form that does not require trust in Doc, in Doc's keys, in Doc's lab, or in any of the camp's social tools. The hot needle works because every piece of the Thing fights for itself; the test is mechanical, repeatable, and verifiable by any observer. See Plot Structure (The Thing) for the rivet structure and Paranoia and Trust as Structure for the longer essay.

"The blood test is a mechanical answer to a problem that was previously framed as a social problem. The whole back half of the film is built around the question: how do you tell? The blood test answers it. The answer requires a shooting first, but it answers it." — Stephen King, Danse Macabre (1981 — King had read the screenplay before publication and discussed Lancaster's draft in print) (book, partial preview at Google Books)

Clark's death is the cost of the new approach

The blood test confirms in beat 34 that Clark's blood passes, meaning he was a man at the moment MacReady shot him in the head in beat 33. The film does not soften this — there is no later scene of MacReady mourning, no acknowledgement from Garry or Nauls. The cost of running the test is paid up front by the killing of an innocent man, and the rest of the post-midpoint approach is conducted in the awareness that this has happened. The film argues, neutrally, that the cost was unavoidable.

"Clark's death is the moral price of the new approach. The post-midpoint approach is right. Clark dies anyway. The film does not flinch from the implication: the right approach is sometimes the approach that kills the wrong man." — Carmen Maria Machado, The Atlantic (2018, on Carpenter's horror)

How the practical effects worked

The Palmer transformation in beat 34 is the film's biggest single-actor practical-effects sequence after the dog-thing kennel. David Clennon sat in the chair he was tied to; the prosthetic body-split rig was built around him on set; the take that made the picture is the one in which Clennon's face is replaced by a prosthetic at the moment the body opens. The torching of Palmer-Thing in the doorway is a separate full-body puppet, operated by Bottin's crew off-stage, with live fire on the rig.

"The Palmer split was one of the most expensive single shots in the picture. We could only do it twice. The first take I had to stop because the prosthetic was wrong. The second take is the one in the picture. Carpenter held on it because we had no third take." — Rob Bottin, Cinefex (1982)

Why Palmer was the reveal

The film's choice to have Palmer be the imitation revealed by the test — rather than Childs, Garry, Nauls, or the absent Blair — is a structural choice that violates audience expectation. The audience has been trained to suspect the men in positions of authority, the men with key access, the men who refuse to be tied. Palmer is the comic-relief stoner. Putting the reveal on him is the film's argument that the test is the only legitimate evidence — the audience cannot know in advance, the camp cannot know in advance, and the test is the test for a reason.

"Lancaster's screenplay does the cleanest possible job of making Palmer unsuspectable for ninety minutes. The audience has ruled him out three times by the time the wire touches the dish. That's the proof the test is doing what no person could do." — Anne Billson, The Guardian (2010s)

What the scene does and does not solve

The blood test resolves the camp's epistemics — Garry, Nauls, and Childs are confirmed human at the moment the test runs — but does not resolve the film's larger problem. Blair is still in the toolshed, untested. Childs is at the entrance, untested as soon as he leaves the room. The test is a snapshot, not a continuous verification. The post-midpoint approach has been given its tool, but the tool has limits the rest of the film will press on. See The Final Standoff and The Open Ending Debate.