Osteogenesis imperfecta (fragilitas
ossium) is an inherited connective tissue disorder characterized by osteoporosis, blue sclera, poor dentition, and mixed deafness.
(He reports that Tesi, nearly 50 at the time, shed 20 years as the heroine, that the wayward Caffarelli as Aeneas `became an actor as far as the Caffarelliana fragilitas
allows', and that Raaff, whom Metastasio had previously found `an excellent singer but a cold performer', advantageously `changed his nature' to play the rough, hot-blooded Iarbas.)(4) He even felt--on one occasion at least--that a good staging could just about survive what he considered a bad score; witness Gluck's `insupportable, arch-Vandal music' for the Viennese revival of his Semiramide riconosciuta the previous year: a show which was saved, indeed sent `starwards', by the `magnificence of the decor' and--a factor he dwells on at greater length--the `excellence of the company'.