Once when I went to see her [Mlle Sontag] I found Soliva there with his young ladies [Gladkowska and Wolkow]. While I was there they sang that duet of his, the one with "barbara sorte" that ends in the major-- you know the one-- and Mlle Sontag told them that their voices were too rough and that, although their training was good, they must produce the voice in a different way if they don't want to lose it altogether within two years.