After searching high and low I, also, cannot find a source to Mark Twain ever stating this.
I did find a reference to Alfonse de Lamartine, making a similar statement to a "Count D'orsey"
book/D'orsey's letters published 1852
link here
External Quote:
1852 The New monthly magazine and universal register.
quote april 23, 1850 Count D'Orsey: "Lamartine me disoit hier: 'Plus je vois des representants du peuple, plus j'aime mes chiens"
translation:
Lamartine told me yesterday: The more I see of the representatives of the people, the more I admire my dogs
This is the earliest actual source I could, find although there are also claims that a
Madame de Staël 1766-july 1817 said:
'The more I see of men the more I like dogs'.
Plus je vois l'homme, plus j'aimie chiens
I haven't been able to verify that yet. She would obviously predate Lamartine.
Either way, although Twain seems he would have shared the sentiment at times and he might have uttered it at a garden party at one time or other, it seems Lamartine would have predated him, as far as possible
origins, as Twain would have been only 14 years old at that time.
External Quote:
Quotes Mark Twain (1835 – 1910) -
In 1851, he began working as a typesetter, contributing articles and humorous sketches to the Hannibal Journal, a newspaper that Orion owned.
He continued to work on the river and was a river pilot until the Civil War broke out in 1861,
He first used his pen name here on February 3, 1863, when he wrote a humorous travel account entitled "Letter From Carson – re: Joe Goodman; party at Gov. Johnson's; music" and signed it "Mark Twain".[26][27]
In 1865, his humorous story "The Celebrated Jumping Frog of Calaveras County" was published, based on a story that he heard at Angels Hotel in Angels Camp, California where he had spent some time as a miner. The short story brought international attention
https://en.wikipedia.org/wiki/Mark_Twain
There was also a similar usage
published 1868.
A. Toussenel: L'esprit des bêtes: Mammifères de France
External Quote:
page 28
La rage, qui fait ressembler les betes a des hommes atteints de fanatisme religieux, n'est pas du chien, mais du loup. One en parlera a sa place. Resumons par un trait notre opinion sure le Chien:
Plus on apprend a connaitre l'homme, plus on apprend a estimer le chien.
which translates to
"Rabies, which makes beasts resemble men of religious fanaticism, is not a dog, but a wolf. One will speak in his place. Let us summarize our opinion on the Dog:
The more one learns to know the man, the more one learns to estimate (
value, respect) the dog."
*most quotes of him online translate it to "admire the dog".