Analysis of On The Posteriors

Because I am by nature blind,
I wisely choose to walk behind;
However, to avoid disgrace,
I let no creature see my face.
My words are few, but spoke with sense;
And yet my speaking gives offence:
Or, if to whisper I presume,
The company will fly the room.
By all the world I am opprest:
And my oppression gives them rest.
Through me, though sore against my will,
Instructors every art instil.
By thousands I am sold and bought,
Who neither get nor lose a groat;
For none, alas! by me can gain,
But those who give me greatest pain.
Shall man presume to be my master,
Who's but my caterer and taster?
Yet, though I always have my will,
I'm but a mere depender still:
An humble hanger-on at best;
Of whom all people make a jest.
In me detractors seek to find
Two vices of a different kind;
I'm too profuse, some censurers cry,
And all I get, I let it fly;
While others give me many a curse,
Because too close I hold my purse.
But this I know, in either case,
They dare not charge me to my face.
'Tis true, indeed, sometimes I save,
Sometimes run out of all I have;
But, when the year is at an end,
Computing what I get and spend,
My goings-out, and comings-in,
I cannot find I lose or win;
And therefore all that know me say,
I justly keep the middle way.
I'm always by my betters led;
I last get up, and first a-bed;
Though, if I rise before my time,
The learn'd in sciences sublime
Consult the stars, and thence foretell
Good luck to those with whom I dwell.