When dose rainsford realize what game zaroff hunts

Rainsford and Zaroff were discussing hunting, and Zaroff alluded to an anial that can reason. Rainsford becomes aware of the "new animal" at this point, as there is only one.... humans.

"I wanted the ideal animal to hunt," explained the general. "So I said, `What are the attributes of an ideal quarry?' And the answer was, of course, `It must have courage, cunning, and, above all, it must be able to reason."'

"But no animal can reason," objected Rainsford.

"My dear fellow," said the general, "there is one that can."

"But you can't mean--" gasped Rainsford.

"And why not?"

"I can't believe you are serious, General Zaroff. This is a grisly joke."