The first possible theme is the idea that the natural, instinctive person is superior to the civilized person and that civilization robs people of their capacity for happiness. Jean-Jacques Rousseau began this idea - often referred to as “the noble savage” - in the 18th Century and it became popular again in the last century and at the beginning of this century when people such as Lawrence noticed that industrialization made workers into machines.
The second possible theme is the fear of death. People have always been scared of dying. But Lawrence had a disease that took many years to kill him. The disease was tuberculosis, also called consumption, which was prevalent in the first half of this century.
The third possible theme is sexual repression which is explained in Sigmund Freud’s theory of psychoanalysis.
The poem shows the conflict between the two parts of Lawrence’s mind: the natural instinctive part and the educated part. When he sees the snake, his instinctive reaction is to see it as an equal.
“Someone was before me at my water-trough,
And I, like a second comer, waiting.”
Even though he is afraid, Lawrence feels honored that the snake has come to his water-trough. “And truly I was afraid, I was most afraid. But even so, honored still more.
That he should seek my hospitality.
From out the dark door of the secret earth.”
The voices of his education tell him,
“He must be killed.
For in Sicily the black, black snakes are innocent, the gold are