InFlowers for Algernon, Charlie and and Algernon become foils for each other, or closely linked characters who share similar traits or have a connection. Charlie meets Algernon fairly early on in the story, but it's not until after the operation that Charlie compares himself to the lab rat for the first time when he writes:
"I hate the tests and I hate the amazeds and I hate Algernon. I never new before that I was dumber than a mouse" (Keyes 20)
Then as Charlie's IQ increases, his resentment of being treated like an experiment builds. He comments in his journal:
" I resent Nemur's constant references to me as a laboratory specimen. He makes me feel that before the experiment was not really a human being."
Later he adds more about his growing frustration with Nemur:
"It may sound like ingratitude, but that is one of the things I hate here - the attitude that I am a guinea pig. Nemur's constant references to having made me what I am, or that someday there will be others like me who will become real human beings. How can I make him understand that he did not create me?"