How we cite our quotes: (Paragraph)
Quote #7
The dog was disappointed [that the man was leaving] and yearned back toward the fire. This man did not know cold. Possibly all the generations of his ancestry had been ignorant of cold, of real cold, of cold one hundred and seven degrees below freezing point. But the dog knew; all its ancestry knew, and it had inherited the knowledge. (16)
Instinct is specifically a kind of primitive knowledge that gets passed down from generation to generation in a species. It's a DNA thing (not that they knew what DNA was back then). The man has lost his instincts when it comes to dealing with the cold because too many generations of his ancestors have lived in more comfortable temperatures. The dog, though, has inherited this knowledge from its ancestors right up until the present day.
Quote #8
The blood of his body recoiled before [the cold]. The blood was alive, like the dog, and like the dog it wanted to hide away and cover itself up from the fearful cold. (20)
There is something in the man that is similar to the dog's instinct, which expresses itself in his (the man's) very blood when he's pushed to extremes.