Modern medical opinion surmises Wilson had had a stroke—he later was diagnosed, as his father had been, with hardening of the arteries. He began to exhibit his father's traits of impatience and intolerance, which would on occasion lead to errors of judgment.[57] When Wilson began vacationing in Bermuda in 1906, he met a socialite, Mary Hulbert Peck. According to biographer August Heckscher II, Wilson's friendship with Peck became the topic of frank discussion between Wilson and his wife, although Wilson historians have not conclusively established there was an affair.[58] Wilson also sent very personal letters to her,[59] which were later used against him by his adversaries.[60]
Having reorganized the school's curriculum and established the preceptorial system, Wilson next attempted to curtail the influence of social elites at Princeton by abolishing the upper-class eating clubs.[61] He proposed moving the students into colleges, also known as quadrangles, but Wilson's Quad Plan was met with fierce opposition from Princeton's alumni.[62] In October 1907, due to the intensity of alumni opposition, the Board of Trustees instructed Wilson to withdraw the Quad Plan.