From a book dated 1902 titled Our Devoted Friend: The Dog
* * *Rev. Dr. George Leon Walker, the late able and beloved pastor of my old church in Hartford, Conn., the First or Centre Church, said to his people in May, 1891, in a sermon on Our Humble Associates: "I have been the possessor of the affection of two dogs, as unlike one another, though of the same nominal breed, as any two men. And when I think of the big heart and boundless passionate love which one of those two creatures gave me, I count it one of the great mistakes, yea, sins of my life that I allowed a friend of mine in a great city to take him to keep awhile, when he mourned for me, as I afterward learned, with constant and inconsolable sorrow, and was finally hopelessly lost, I doubt not in unavailing effort to find me again. I hope no one here will smile when I say, solemnly, that the pain of that poor heart has lain upon me for near twenty years a remorse and a burden."
Author: Mrs. Sarah Knowles Bolton, published in Boston by L.C. Page & Company, pages 324-325. I think I have found a picture of this good Reverend here.