a dog miscalculates, a poet chuckles

From The Poets' Beasts by Philip Stewart Robinson:  the author pauses during a pages-long complaint on how some folks love their dogs far too much, and muses on a couple of comic verses where dog folly is pointed up if not outright celebrated.
* * *
. . . Yet the dog is a beautiful symbol, and though here and there individuals may exceed into Egyptian idolatry of the animal, it is as a type of courageous, self-forgetful friendship that the poets use it most justly.
Occasionally, too, they confess that the best of dogs may "from the path of duty err." As Somerville admits—

"He may mistake sometimes, 'tis true,
None are infallible but you;
The dog whom nothing can mislead
Must be a dog of parts indeed ;"

and as Eliza Cook delightfully illustrates in her address to the staghound Bran—

"You have strength of muscle and length of limb,
Your jaws are deep and your beard is grim,
Your fangs are strong and ivory white,
Your mouth is as black as a cloudy night.
'Tis pleasant to hear the wise ones utter
The worth of your power and pace;
But why did you swallow that pound of butter,
Dog of an ancient race?"

* * *
I believe the Eliza Cook to whom he refers is this one.  Selection from The Poets' Beasts, Philip Stewart Robinson (Chatto and Windus, 1885), p. 308.