p. 152 Canon XL.
Bishops called to a synod must not be guilty of contempt, but must attend, and either teach, or be taught, for the reformation of the Church and of others. And if such an one shall be guilty of contempt, he will condemn himself, unless he be detained by ill health.
By ἀνωμαλία, illness is commonly understood, and Dionysius Exiguus and Isidore translated it, the former ægritudinem, and the latter infirmitatem. But Balsamon justly remarks that the term has a wider meaning, and, besides cases of illness includes other unavoidable hinderances or obstacles.