In Chapter 18 of Anne of Ingleside, Jem’s new dog Gyp dies.

Gyp died the next morning. It was the first time death had entered into Jem’s world. No one of us ever forgets the experience of watching something we love die, even if it is “only a little dog.” Nobody at weeping Ingleside used that expression, not even Susan, who wiped a very red nose and muttered:

“I never took up with a dog before . . . and I never will again. It hurts too much.”

Susan was not acquainted with Kipling’s poem on the folly of giving your heart to a dog to tear; but if she had been she would, in spite of her contempt for poetry, have thought that for once a poet had uttered sense.

The Power of the Dog is also the title for Chapter 6 of Magic for Marigold, where Marigold is frightened (rather than sentimentally moved) by the power of a dog.

The Power of the Dog
by Rudyard Kipling

There is sorrow enough in the natural way
From men and women to fill our day;
But when we are certain of sorrow in store,
Why do we always arrange for more?
Brothers and sisters, I bid you beware
Of giving your hearts to a dog to tear.

Buy a pup and your money will buy
Love unflinching that cannot lie -
Perfect passion and worship fed
By a kick in the ribs or a pat on the head.
Nevertheless it is hardly fair
To risk you heart for a dog to tear.

When the fourteen years that nature permits,
Are closing in asthma, or tumor, or fits,
And the Vet’s unspoken prescription runs
to lethal chambers or loaded guns,
Then you will find - it’s your own affair
But - you’ve given your heart to a dog to tear.

We’ve sorrow enough in the natural way
When it comes to burying Christian clay.
Our loves are not given, but only lent
At compound interest of cent per cent,
For when debts are payable, right or wrong,
A short time loan is as bad as a long -
So why in Heaven (before we are there)
Should we give our hearts to a dog to tear?

When the body that lived at your single will,
When the whimper of welcome is stilled
(HOW STILL!)
When the spirit that answered your every mood
Is gone - wherever it goes - for good,
You soon discover how much you care,
And give your heart to a NEW dog to tear.

Source

http://www-hsc.usc.edu/~rneville/dogpoem3.html