Sentence:  However, I am not prone to sensitiveness, and the following of a sense of duty, wherever it may lead, has always been a kind of <WSD>fetich</WSD> with me throughout my life; which may account for the honors bestowed upon me by three republics and the decorations and friendships of an old and powerful emperor and several lesser kings, in whose service my sword has been red many a time. 
Meaning of the word marked with <WSD> tags:  An irrational, or abnormal fixation or preoccupation; an obsession. (from the 19th c.)