Gene feels that there is a contrast between Brinker Hadley, who arrives for the serious winter season, and Finny, his friend during what he calls "the gypsy days" (page 75). Brinker is described as "the standard preparatory school article in his grey gabardine suit with square, hand-sewn-looking jacket pockets, a conservative necktie, and dark brown cordovan shoes" (page 87). Brinker is the center of the class and, unlike Finny, is concerned with politics and school offices. He seems to represent the seriousness and studiousness required of the winter session at school, unlike Finny, the leader during the school's summer session, who was playful and daring. The absence of Finny and the return of Brinker, who immediately accuses Gene of trying to get rid of Finny, symbolizes the end of the more fun summer session and the return of the usual grind and seriousness during the winter. 

Brinker deals with the "business" of the school. He's involved in school politics and debate. He focuses on the in and outs of the school happenings. He sees it as his job to keep everyone is his place and focused on the correct goals. Brinker is the one who pushes Gene toward a decision about signing up for service. When Gene says this about Brinker, it is his reponse to coming off the carefree summer with Finny. Finny was about rule-breaking and enjoying being a boy. Even the summer classes that Gene takes are optional. When Finny is gone along with the summer, it's back to "business" with Brinker and the serious winter session. Gene falls under Brinker's serious spell, just like he fell under Finny's fun-loving one.