From the evidence London gives us, what stages are involved in the process of freezing to death? What does the story gain from London's detailed account on the man's experience with each successive stage?

The limbs and nerves can no longer be felt. There is panic and the man runs though this will just further exhaust him. Finally the man lies in the snow and hallucinates. He feels sleepy and his body begins to shut down until he is dead. This process illustrates the natural order of things. Man is merely a mammal subject to the same unforgiving elements as any other animal. When man makes a mistake or disrespects nature, he pays the price. London wants to underscore how the body succumbs to cold. There is no heroics or human miracles; he dies according to how the human body reacts to freezing.