Sentence:  When letters were in their infancy, and when knowledge and the arts were groping their way through seemingly impervious mists, some splendid name was necessary to give an author celebrity—hence the custom of <small>DEDICATIONS</small>; hence those floods of adulation, which poured from the press, and outraged the feelings of the <WSD>addresser</WSD> and the addressed. 
Meaning of the word marked with <WSD> tags:  A person who addresses someone (directs spoken or written communication toward someone).