Whitman declares that his contribution to the "unfolding of words of ages" will be the phrase, "en masse," which means "in mass" in French.
En masse is a democratic word, a word for the non-exclusive philosophy that Whitman has been presenting.
He goes on to praise scientists and all the work they do, but then he claims that for him scientists are just the means to an end and not the end itself. You cannot "live" with just the facts of science to guide you.
He cares about life more than about scientific properties.
Also, he doesn't like people who repress their sexuality.