…Peirce regards a proposition, by which he means the substance of a judgment considered as abstracted from the assent to it or dissent from it, a symbol which has a part by which it separately indicates its object while it also signifies this object in another way. The genus is the dicisign…
This quote has been taken from Kenneth Laine Ketner's 1983 reconstruction of Peirce's 'Autobiography'. Ketner identifies the source as "variant pages" of the manuscript.
http://www.commens.org/dictionary/entry/quote-brief-intellectual-autobiography-charles-sanders-peirce-24