Following Swamp Thing's apparent death in the previous issue, Sunderland has his body shipped to his fully-automated Washington lab for cryogenic preservation. Still intent on discovering how Alec Holland's bio-restorative formula transformed him,note he arranges for the release of the jailed villain Dr. Jason Woodrue, AKA the Floronic Man, and hires him to dissect and study the creature's anatomy. (Like Holland, Woodrue is a botanist who became a plant/human hybrid, albeit intentionally in his case.)
Over the next six weeks, Woodrue analyzes the Swamp Thing's organs one by one, finding, to his confusion, that none of them could possibly perform the functions they would in a human body, as they're made of coarse plant fibre and otherwise lack the proper physiological structure. Finally, Woodrue's chance reading about a biology experiment gives him the answer. He excitedly explains to an impatient Sunderland that planarian worms unable to run a maze were, after being fed worms that the researchers had trained to do so, then able to run it. From this, he deduces that "consciousness and intelligence can be passed on as foodstuffs."
Thus, Woodrue theorizes, by the time Holland's burning, formula-saturated body landed in the swamp, he was already dead. However, his consciousness somehow survived, and the swamp plants that ingested his body became "infected" with it. The newly-sapient but confused plant mass then semi-consciously shaped itself over time into a quasi-human form. Therefore, Woodrue tells his employer, the Swamp Thing is not in fact Alec Holland, a human being transformed into a plant. Rather, he's a plant that thought it was Holland and thus did its best to transform itself into a human being.
However, just as Woodrue is about to explain the most important implication of all this, Sunderland cuts him off and fires him, saying his scientists can do the rest. He then exits the room, leaving the vengeful, computer-savvy Woodrue alone with the console which controls everything in the lab. This includes the cryogenic freezer containing the swamp creature, whom he proceeds to thaw because, as he reflects that evening at home, if the Swamp Thing is really a plant, that means bullets can't kill it, only put it into a state of shock. Soon enough, at the lab, Sutherland discovers the empty freezer and hurries to his office to summon help...only to encounter the revived Swamp Thing, who's just finished reading Woodrue's report on him.
As the enraged Swamp Thing chases his captor through the lab, Woodrue thinks that the only thing that could've kept the creature sane all this time was the hope that he could one day regain his humanity. However, now that he knows he isn't, never has been and never will be human, all bets are off. And sure enough, at the lab, Sunderland, trapped by the doors that (thanks to Woodrue) no longer recognize his I.D., succumbs to strangulation at the Swamp Thing's hand. Woodrue imagines that the creature would head back to the Louisiana swamplands, and resolves to follow him there.
- Artistic License Biology: The planarian worm study that Woodrue describes was one of a series of such experiments (some involving mazes, others involving light stimulus response) performed by James V. McConnell and others in the 1950s and 1960s, testing the "memory RNA" hypothesis. However, subsequent researchers failed to replicate his results, and it was eventually determined that the second, "cannibal" group of worms were merely following slime trails that the first group of worms had left behind in the maze.
- Book-Ends: Woodrue's observation, "It's raining in Washington tonight," opens and closes the issue.
- Brain Food: Woodrue theorizes that consciousness and intellect can be transferred, from one organism to another, as food, and relates this to the ritual consumption, in some cultures, of a deceased elder in order to gain his wisdom. "General, you could go into a delicatessen and order Einstein on pumpernickel...''
- Dead All Along. Played with. Woodrue, and the Swamp Thing himself, discover that Alec Holland died almost immediately after catching fire, meaning that the being thought to be him has simply been borrowing Holland's identity and memories without knowing it.
- Digging Yourself Deeper: The frightened Sunderland, encountering the revived and furious-looking Swamp Thing, manages to say precisely the wrong thing.
- Failure Is the Only Option: What Swamp Thing discovers regarding the quest for his lost humanity. Moore stated that he deliberately wanted to remove the "carrot-and-stick" because Holland's quest to become human again would have ended the series and kept it in a permanent abyss of failure. By resolving once and for all, that Swamp Thing never will be (and never was) a human, the story was no longer bound by its Driving Question.
- Go Mad from the Revelation: Swamp Thing's reaction to learning he can never regain what he never had in the first place.
- Immune to Bullets: Played with. A bullet through the head can temporarily put the title character out of commission, but can't kill him.
- Killed Off for Real: This is Sunderland's last appearance alive. (He appears as one of the damned in Hell, in Swamp Thing Annual #2.)
- Oh, Crap!: Sunderland has such a moment when he discovers the Swamp Thing has escaped his freezer. He has an even worse one when he encounters the creature face-to-face and learns that he's read Woodrue's report.
- Plant Person: Deconstructed in the Swamp Thing's case. Dissection reveals that he can't be a human being chemically transformed into a humanoid plant, because plant tissue can't support the functions of human organs. On the other hand, the trope is played straight with Woodrue, the Floronic Man, whose successful chemical self-transformation into a humanoid plant is never questioned.
- Purple Prose: Woodrue's narration opens with this bit of whimsy:It's raining in Washington tonight. Plump, warm summer rain that covers the sidewalks with leopard spots. Downtown, elderly ladies carry their houseplants out to set them on the fire-escapes, as if they were infirm relatives or boy kings.
- Retcon: The title character's reimagined origin is one of the most radical and longest-lasting examples in comic book history.
- Revenge: Woodrue gets back at Sunderland for firing him (and, presumably, planning on returning him to prison) by thawing the Swamp Thing.
- Rogues-Gallery Transplant: Prior to this issue, the Floronic Man (known as the Plant Master before his self-transformation) was a minor villain in The Atom and Batman stories.
- Sanity Slippage: The Swamp Thing acts with uncharacteristic, unthinking savagery at the issue's climax. The revelation he learns, though, when his sanity does slip is slightly justifiable...
- Science Is Useless
I am not, in your terms, an intelligent man. I am merely shrewd. Being "merely shrewd" has secured me a vast financial empire and has enabled me to watch while cleverer men went penniless to their graves [...] You see, I am very rich. I do not need to be an intellectual [...] I do not need the ramifications. I do not need the "correct background." And you, Dr. Woodrue, now that you've provided me with my breakthrough...I need you least of all.
- Sunderland displays this attitude when he chews Woodrue out for insisting he doesn't have the required knowledge to understand the full implications of his discovery about the Swamp Thing:
- Then he foolishly leaves Woodrue alone with his computer, and Woodrue does have the "correct background" to subvert Sunderland's security systems.
- The issue's title is an allusion to the 1632 Rembrandt painting, The Anatomy Lesson of Dr. Nicolaes Tulp, which depicts a physician lecturing on the musculature of the arm, using a dissected cadaver.
- The Splash Panel features an outline of a dissected human body, resembling the opening title card of the 1959 courtroom drama, Anatomy of a Murder.
- Straw Character: Sunderland, created by previous writer Marty Pasko, had always been a Corrupt Corporate Executive, willing to dissemble, steal, kidnap and even murder in pursuit of his research company's objectives. However, in this his final appearance alive, he comes across additionally as a conservative political strawman, telling Woodrue his lab is fully automated because it "spares me a lot of grief with labor relations" and mocking Alec and Linda Holland for working together as scientists: "You know these people...liberal, equal relationships. Caring and sharing."
- Tomato in the Mirror: The protagonist realizes he isn't, never has been, and never will be Alec Holland.
- Was Once a Man: Subverted. No he wasn't, as it turns out.
- Wham Episode: "He isn't Alec Holland. He never will be Alec Holland. He never was Alec Holland. He's just a ghost. A ghost dressed in weeds."
- Wham Line: See page quote.
- You Are Who You Eat: Subverted. The swamp plants that consumed Holland's consciousness didn't actually become him, any more than Holland became a plant. Rather, the vegetation now thought it was Holland, not realizing the real person by that name was dead and his body was decomposed.