Truth, Not Form!

I came upon a fountain on my way
When it was hot, and sat me down to drink
Its sparkling stream, when all around the brink
I spied full many vessels made of clay,
Whereon were written, not without display,
In deep engraving or with merely ink,
The blessings which each owner seemed to think
Would light on him who drank with each alway.
I looked so hard my eyes were looking double
Into them all, but when I came to see
That they were filthy, each in his degree,
I bent my head, though not without some trouble,
To where the little waves did leap and bubble,
And so I journeyed on most pleasantly.