Martin finally finds himself in Max Gottlieb's bacteriology class. Gottlieb, during his lecture, shows himself to be a highly knowledgeable and intelligent man, taking from science, literature, and philosophy. Most of the students do not have a great affinity for Gottlieb, and, at most, they find him useful and admirable as is illustrated by the discussion the students have about the professor after his class. However, Martin can relateto him and to what he does in his laboratory. He imagines himself working the way Gottlieb works.
He is quite happy in Gottlieb's bacteriology class, and he begins to work late nights in the laboratory. Gottlieb sees him working late one night and invites him to join him for some sandwiches. The sandwiches seem wonderful and foreign to Martin, and he loses himself in the experiences that Gottlieb recounts to him. The two men forge a kind of friendship or a tutorial/mentor relationship. Gottlieb tells him of the times he spent in London and Stockholm, he tells him of Marseilles. He tells him also of his children and encourages Martin. Gottlieb notes that he will probably not make a good physician but, instead, a good laboratory scientist.
Completely enthralled in bacteriology, Martin becomes humbled as to the amount of knowledge he does not yet have. He shows himself to be rebellious in medical classes, to professors, and in conversations with friends and even considers dropping medicine and specializing in bacteriology.
He feels as though he has no one to speak with about this turmoil inside of him. He cannot speak to Clif, his roommate, because Clif rarely takes anything seriously, and so he finds a willing ear in Madeleine, who is always "sympathetic and sensible." Martin believes that Madeleine truly understands him and decides that he wants to marry her.
Madeleine is, however, not all together perfect. She is what Martin calls an "improver," a woman who is always trying to "improve" or change her man in the ways of vocabulary, taste, etc. Still, Madeleine, in her good moments opens up to him and, one time in particular, admits that she herself is "ordinary" despite all her appearances and her "bluffing." Martin proposes to Madeleine and even promises to become the "successful" doctor he has, until this point, adamantly criticized, in order so that they may have everything they want.
Their relationship continues to have its ups and downs, even after the proposal. Martin promises Clif that he will work as a waiter with Clif during the summer at a hotel in Canada, a promise to which Madeleine snobbishly opposes. She does not want him to be a lowly waiter. They break off their engagement twice. The last time happens right before Martin leaves with Clif for the summer. And although he has broken up with Madeleine, Martin is excited for the coming year because Gottlieb has appointed him as an undergraduate assistant.