I have lost, within these last few days, a little bull-dog.
He had just completed the sixth month of his brief existence. He had no history. His intelligent eyes opened to look out upon the world, to love mankind, then closed again on the cruel secrets of death.
OUR FRIEND THE DOG
By Maurice Maeterlinck.
Illustrated by Cecil Aldin.
Dodd, Mead & Company: New York. 1913.
Elephant's Picture Book 
On the positive side, we don’t know that death’s secrets actually ARE cruel at all.
Perhaps it was the loss of the dog that came as a cruel experience for the author – easy to get confused by grief. I would hate to think my dogs faced anything cruel after death – they deserved nothing less than ecstasy.
Elephant