to integrate the deaf and hard of hearing with the hearing world. Bell encouraged speech therapy and lip reading over sign language. He outlined this in a 1898 paper detailing his belief that with resources and effort, the deaf could be taught to read lips and speak (known as oralism) thus enabling their integration within the wider society. Bell has been criticised by members of the Deaf community for supporting ideas that could cause the closure of dozens of deaf schools, and what some consider eugenicist ideas. Bell did not support a ban on deaf people marrying each other, an idea articulated by the National Association of the Deaf (United States). Although, in his memoir Memoir upon the Formation of a Deaf Variety of the Human Race, Bell observed that if deaf people tended to marry other deaf people, this could result in the emergence of a "deaf race". Ultimately, in 1880, the Second International Congress on Education of the Deaf passed a resolution preferring the teaching of oral communication rather than signing in schools. Continuing experimentation In 1872, Bell became professor of Vocal Physiology and Elocution at the Boston University School of Oratory. During this period, he alternated between Boston and Brantford, spending summers in his Canadian home. At Boston University, Bell was "swept up" by the excitement engendered by the many scientists and inventors residing in the city. He continued his research in sound and endeavored to find a way to transmit musical notes and articulate speech, but although absorbed by his experiments, he found it difficult to devote enough time to experimentation. While days and evenings were occupied by his teaching and private classes, Bell began to stay awake late into the night, running experiment after experiment in rented facilities at his boarding house. Keeping "night owl" hours, he worried that his work would be discovered and took great pains to lock up his notebooks and laboratory equipment. Bell had a specially made table where he could place his notes and equipment inside a locking cover. Worse still, his health deteriorated as he had severe headaches. Returning to Boston in fall 1873, Bell made a far-reaching decision to concentrate on his experiments in sound. Deciding to give up his lucrative private Boston practice, Bell retained only two students, six-year-old "Georgie" Sanders, deaf from birth, and 15-year-old Mabel Hubbard. Each pupil would play an important role in the