How did Helen's family become acquainted with the Perkins Institution?

Helen relates this progression of events in Chapter 3 of The Story of My Life. The Keller family lived in Alabama and didn’t know anyone in the area who could help Helen learn to communicate. Her mother had read the travel narrative American Notes by Charles Dickens. In it she had read of the work of Dr. Samuel Gridley Howe at the Perkins Institution, now known as the Perkins School for the Blind, near Boston. The Kellers now became aware that such help was possible. They first went to see Dr. Chisholm in Baltimore. He recommended contacting Alexander Graham Bell in Washington, D.C. Bell in turn told them to write a letter to Mr. Anagnos at the Perkins Institution. By the summer of 1886, Anagnos let them know that a teacher had been found for Helen. Anne Mansfield Sullivan arrived at the Keller house in March 1887.