This issue comes up in the 19th chapter, titled “In Which I Have a Good Look at Winter and Find Spring in the Snow.” Sam Gribley has been living on his own in the Catskill mountains since May. Near the end of the following January, Sam feels tired. He decides that his current diet must be missing some essential vitamin, but he doesn’t know which one it is. He gets a nosebleed, too. When his falcon Frightful catches a rabbit for him, Sam finds himself craving the liver. He learns later that liver is rich in vitamin C. As long as he eats liver on a regular basis in these winter months, he has no more problems. But he can’t wait for spring to come, when fresh greens will be available again.