In the opening paragraphs of  By the Shores of Silver Lake , Laura Ingalls Wilder told of the scarlet fever that Ma, Mary, Carrie, and baby Grace all experienced. Though the doctor bill would be a difficult to pay, the larger concern was that the scarlet fever had left her sister, Mary Ingalls, blind. We must remember that Laura Ingalls Wilder wrote about her childhood in the Little House books, but…