The plot of the story
A deaf-mute janitor Gerasim, serve the old lady had a lover – a washerwoman Tatiana, a piece of bread and a roof over my head. One day Gerasim saves out of water drowning the dog and decides to keep it, giving the rescued named "Mumu". Over time, the janitor is tightly tied to the animal and takes care of him like my own child. Especially his feelings towards Mumu strengthened after the lady gives his beloved Tatyana for alcoholic Capito, without asking the consent for this marriage.
In those days landowners were known for their impunity and poor against a fortress.
One day the lady heard the night barking Mumu and ordered Gerasim to drown the dog, which annoyed her. Pity for the animals the lady was not tested, because in the old days dogs were considered to be exclusively of the guards of the yard, and if they could not protect him from robbers, the use of them was not. Gerasim, as a simple land without the right to vote, could not obey the mistress, so he had to sit in the boat and drown the only native creature. Why is Gerasim just do not let go Mumu at will?
Psychological explanation
From Gerasimos gradually took away all his village, the peasant work, the woman finally, a little dog, to which he became attached with all my heart. He killed the Mumu, because it recognized that affection for her made him dependent on the senses – and since Gerasim constantly suffered from losses, he decided that this loss will be the last in his life. Not the last role in this tragedy played and the psychology of a serf, who from childhood knew that landlords can't disobey, because it is fraught with punishment.
In the old days the Orthodox Church denied the existence of the soul in all animals, so get rid of them with ease and indifference.
At the end of the story by Turgenev, says the head never came up to the dogs and nobody got married. From a psychological point of view, it is understood that dependent and vulnerable doing it love and affection. After the death of Mumu Gerasim had nothing to lose, so he spat on serfdom and returned to the village, protesting against the tyranny of a lady. Gerasim could leave Mumu alive – but he was frightened that the lady would think of her a more terrible punishment that would force Gerasim to worry even more, so he chose to take her own life, not someone else's hands.