To begin his test in the garden, Klausner plugs a pair of headphones into the sound machine. The narrator comments that Klausner is so pale, small, and thin that he looks like an ancient, consumptive, bespectacled child. The sun has gone down and there is no wind or sound. A woman in the next garden over walks with a flower basket on her arm. Klausner watches her without thinking about her. He flicks a switch on the box, then adjusts the dials to move the needle and volume. The dial is marked with numbers starting at 15,000 and going up to 1,000,000.
Klausner listens intently, head cocked to the side. He hears a faint, spasmodic crackling, behind which he can hear a distant humming tone. He becomes aware of a curious sensation in which his ears feel as though they are stretching out away from his head as if on a thin, tentacle-like wire. His ears feel as if they are stretching to a forbidden ultrasonic region where ears have never been before and have no right to be.
Suddenly Klausner hears a piercing shriek. He jumps back and looks around for the person who made the sound, seeing only the woman calming cutting yellow roses and putting them in her basket. The shriek comes again. The sound is throat-less and inhuman, clear and cold. There is a metallic quality Klausner has never heard. He looks around and hears the shriek when the woman makes another cut—the exact moment when she cuts the rose stem.
Klausner shouts the woman’s name—Mrs. Saunders—with a thrill of excitement. Mrs. Saunders sees becomes alarmed to see her neighbor waving his arms and shouting. Klausner asks her to cut another rose. She asks why and he simply asks her please to cut just one more. The narrator comments that she always believed Klausner to be a peculiar person; now it seems he’s gone completely crazy. She wonders if she should fetch her husband but humors him. She bends down and snips another rose.
Again Klausner hears the throat-less shriek. He removes his headphones and runs to the fence, saying that’s enough, she need not cut another. Klausner puts his hands on the fence and explains that each stem she cut screamed in the most terrible way. Klausner breathes rapidly, trying to control his excitement. He says each rose released a cry of pain at approximately one hundred and thirty-two thousand vibrations per second. She couldn’t possibly have heard it, but he did.
Mrs. Saunders asks if he really did hear it, having decided she would a dash for the house in five seconds. Klausner says she would be right to believe a rose bush with no nervous system wouldn’t feel pain, but he asks how she knows this is the case; how does she know a rose doesn’t feel the same pain as a person whose wrist has been cut? The rose is alive, after all.
Mrs. Saunders agrees and wishes him a good night before running back to her house. Klausner goes back to the table and puts on his headphone. He plucks a daisy from his lawn and pulls the stem. He hears a faint cry—not of pain, but surprise. A single emotionless note expressing nothing. He realizes it was the same with the roses, and so he was wrong to call it a cry of pain. It felt more like something humans didn’t know about: toin or spurl or plinuckment or some other invented word.
Klausner removes his headphones and looks around to see lights on in the houses; it is dark. He puts the box in the workshop and returns to his home. He wakes the next morning as soon as it is light, dresses, and goes straight to the shed. He carries the black box, walking unsteadily against its weight, out to the park across the road from his front gate. He puts the machine close to the trunk of a large tree and then quickly goes back to the house to get an axe from his coal cellar.
At the tree, he looks around nervously in every direction. There is no one around because it is six in the morning. He switches the machine on and puts on his headphones. He hears a faint familiar humming sound. He picks up the axe and swings it at the trunk of the tree as hard as he can. The blade cuts deep and stays lodged in the wood. He hears an extraordinary new noise: a harsh, noteless, growling, low-pitched screaming. Unlike the roses’ short shriek, the tree’s noise is like a sob, lasting for a minute and gradually fading.
Klausner stares in horror at the axe sunk into the tree. He gently removes the axe and throws it on the ground. He touches the gash in the wood, trying to press the edges together to close the wound while apologizing to the tree and insisting it will heal. He stands for a moment before hurrying to his house to consult the phone book and dial the doctor’s number.
Just as he opened the story by showing Klausner calmly tinkering with his sound machine, Dahl starts the story’s second major scene by depicting Klausner calmly going about his first test in the garden. As Klausner tunes the dials, the narrator digresses to describe Klausner’s physical appearance. The narrator emphasizes Klausner’s small stature and paleness to underscore the idea that Klausner is unwell. However, it is unclear whether his physical appearance is because of mental illness or merely due to neglect of his personal care that results from his obsessive focus on his sound machine.
To illustrate how the sound machine enhances Klausner’s ability to hear, Dahl uses metaphor and simile, describing the invisible sensation of extended hearing range as thin, tentacle-like wires growing out of Klausner’s ears. Having expanded his audible range, Klausner hears a piercing shriek when Mrs. Saunders, his neighbor, snips a rose stem in her garden.
Although the sound has a metallic quality, Klausner does not question whether the sound he hears is an application of the garden shears Mrs. Saunders uses; instead, he immediately jumps to the theory that the roses must be screaming in pain. With this turn of events, Dahl introduces the theme of the personification of plants. Attempting to articulate his findings to Mrs. Saunders, Klausner grows so excited that he frightens Mrs. Saunders, who humors him while privately wanting to dash inside to safety.
Just as the doctor privately evaluates Klausner’s mental stability based on his ramblings and manic behavior, Mrs. Saunders perceives Klausner as a madman, not a genius. Dahl again sows doubt in the reader’s mind by using multiple narrative points of view to inject more ambiguity into the story. In doing so, Dahl promotes critical thinking in readers, who must evaluate for themselves whether Klausner is a genius inventor, a madman, or both.
Klausner, oblivious to Mrs. Saunders’s discomfort and speedy exit, performs another test by plucking a daisy from his lawn. After hearing a faint noise of surprise, Klausner puts the machine away and wakes early the next morning to conduct another test on a tree in the park across from his house. The desire to scale up his experiment matches Klausner’s growing obsession with his findings. Commensurate to its size, the pained sound the tree produces in response to Klausner’s axe is low, growling, and long-lasting. Klausner’s sensitivity emerges as he feels the horror of the pain he has caused, personifying the tree in imagining it has human feelings.