"The Parasite: A Story" by Arthur Conan Doyle is a psychological horror tale that delves into the unsettling effects of hypnotism and mind control. The story follows Professor Gilroy, a skeptical scientist who becomes the subject of an experiment in hypnotism conducted by Miss Penelosa, a woman with mysterious and sinister abilities. As the experiment progresses, Gilroy finds himself increasingly under Miss Penelosa's control, losing his will and autonomy as she manipulates his thoughts and actions. What begins as a scientific curiosity quickly spirals into a terrifying ordeal, as Gilroy becomes obsessed with the power, Miss Penelosa holds over him.The novella explores the supernatural influence that Miss Penelosa exerts, highlighting the fear and anxiety that comes from losing control over one's mind. Gilroy's experience raises ethical questions about the dangers of scientific experimentation, particularly, when it involves tampering with the human psyche.Set against the backdrop of Victorian society, "The Parasite" reflects the era's fascination with the supernatural and the fear of the unknown. Doyle uses the story to examine the darker side of human nature, illustrating the terror that can arise, when the boundaries between science and morality are crossed.
