The following quote is from "Mansfield Park" by Jane Austen:
Fanny was left with only the Crawfords and Mr. Yates. She had been quite overlooked by her cousins; and her own opinion of her claims on Sir Thomas's affection was much too humble to give her any idea of classing herself with his children, she was glad to remain behind and gain a little breathing time. Her agitation and alarm exceeded all that was endured by the rest, by the right of a disposition which not even innocence could keep from suffering. She was nearly fainting. What does "which" refer back to? Is it "a disposition" or "her agitation and alarm"?
I have consulted almost all the dictionaries I could lay my hands on, but could not find the expression "by the right of". The only one I can find is "by right of". I wonder whether they mean the same thing and "by the right of" is dated form. And another thing, what is the right interpretation of "not even innocence could keep from suffering".