In these lines, he is painting a picture of the polite, structured, expected routine that many of the gatherings that he attends has. His expressions indicate a bit of frustration with his guests and the fact that every gathering is the same:
"For I have known them all already, known them all:—
Have known the evenings, mornings, afternoons,
I have measured out my life with coffee spoons;"
Instead, he wants to "disturb the universe," disrupting their safe little world by asking a question that will change everything. But, the tedious, formal routine drowns out all else. He also expresses his feelings of insignificance and inadequacy when in the presence of those guests-especially female ones. He is intimidated by them, fascinated by them, and scared of them all at once. He says,
"The eyes that fix you in a formulated phrase,
And when I am formulated, sprawling on a pin,
When I am pinned and wriggling on the wall,
Then how should I begin,"
comparing himself to an insect, pinned, helpless, and under intense scrutiny and analysis by these guests. It makes him uncomfortable, and question his motives. He is fascinated by the female guest:
"Arms that are braceleted and white and bare
[But in the lamplight, downed with light brown
Is it perfume from a dress
that makes me so digress?"
Here he expresses his fascination with them, but at the same time, that same resignation that everything is the same as always, and how he doesn't dare change that.
All in all, he expresses an intense insecurity in the presence of those guests that fascinate and intimidate him, along with a quiet frustration at the meaningless conversation and time spent. All he wants to do is speak his heart, openly, but that would disrupt the routine and bring further scrutiny upon himself, which he fears above all.