Whitney is introduced at the beginning of the story. Both Rainsford and Whitney are expert hunters. They are going to hunt jaguar in Rio de Janerio and the Amazon. They both love hunting.
The disagreement they have is Whitney believes that it is great sport for the hunters, but not for the jaguar. He believes that the animals experience fear "the fear of pain and the fear of death." Rainsford objects and says,
"This hot weather is making you soft, Whitney. Be a realist. The word is made up of two classes - the hunters and the hunted. Luckily, you and I are the hunters." (pg 2)
This statement will haunt Rainsford later when he becomes the hunted.
" Rainsford did not want to believe what his reason told him was true, but the truth was as evident as the sun that had by now pushed through the morning mists. The general was playing with him! The generals was saving him for another day's sport! The Cossack was the cat; he was the mouse. Then it was that Rainsford knew the full meaning of terror." ( pg 13)
When Whitney tells him of the superstitions the sailors felt about the island, Rainsford says
"Pure imagination," said Rainsford. "One superstitious sailor can taint the whole ship's company with his fear." (pg 2)
Whitney disagrees and says,
"Maybe. But sometimes I think sailors have an extra sense that tells them when they are in danger. Sometimes I think evil is a tangible thing --- with wave lengths, just as sound and light have." (pg 2)
The evil of the island also comes true for Rainsford. There is a reason the sailors call it Ship Wreck Island.
Whitney is used by the author to introduce the evil of the island and set a standard for Rainsford. From this conversation we can see how much Rainsford changes through his horrible experience onthe island.