From Stray Dog to Experiment
The Heart of a DogThis central transformation follows Sharik from a wounded street dog into a humanized being whose conduct exposes the limits of scientific creation.
increasing
Bearing strength in each event
decreasing
Scalded in the Snow

A Wounded Stray
Street Survival
Sharik suffers a severe scald after a cook throws boiling water on him. Injured and cold, he imagines the hunger and sickness that could finish him.
A Chance Encounter
A passerby offers him sausage and kindness. Sharik follows the stranger toward warmth, trusting the person who has suddenly made survival possible.
Shelter and Healing

A New Household
Recovery
Professor Preobrazhensky brings Sharik into his apartment and treats his wound. Food, heat, and safety replace the street's daily struggle.
Dependence
Sharik attaches himself to the professor, whose protection gives him comfort and status. The collar soon changes how porters and other dogs respond to him.
The Transplant Operation

A Radical Intervention
The Procedure
Professor Preobrazhensky and Doctor Bormenthal transplant human testes and a pituitary gland into Sharik. The operation is dangerous, and the dog nearly dies.
Uncertain Outcome
The doctors watch for signs of survival, not knowing that the procedure will produce a transformation unlike the rejuvenation they had studied. Sharik's recovery becomes the experiment's first unsettling result.
A Human Form Emerges

Speech and Transformation
Rapid Change
Sharik loses much of his fur, grows, stands upright, and begins speaking. His first words draw on the coarse street language he absorbed as a dog.
Scientific Astonishment
Doctor Bormenthal records the changes as evidence that the experiment has produced humanization rather than rejuvenation. The creature's language and body advance faster than his judgment.
Creation Becomes a Crisis

The Experiment's Cost
Social Harm
As Poligraph Poligraphovich Sharikov, the former dog becomes violent, dishonest, and dangerous. His official position and political connections intensify the threat inside the household.
Reversal
Professor Preobrazhensky and Doctor Bormenthal restore him to canine form. The ending closes the experiment's immediate crisis but leaves its ethical and scientific implications unresolved.
Early in the story, on a winter afternoon
That evening and the following days
December 23, 1924
Late December 1924 to January 1925
Near the ending