The Vivisectionist - 1915 I was released on:

USA: 23 June 1915

The Vivisectionist - 1915 II was released on:

USA: 2 June 1915

USA: 17 September 1915 (re-release)

Most definitely, Mark Twain had pets. He once wrote "A home without a cat -- and a well fed, well petted, and properly revered cat -- may be a perfect home, perhaps, but how can it prove title?" And he and his wife and daughters had a series of cats at their home in Hartford. They also owned collie dogs, garden ducks, and at least one pony.

In addition to his lovely quote about cats, Twain had many positive things to say about dogs - including this one: "Heaven goes by favor. If it went by merit, you would stay out and your dog would go in."

Later in life, Twain supported efforts of the Society for the Prevention of Cruelty to Animals and the Anti-Vivisectionist League.

source for the information: Gregg Camfield, The Oxford Companion to Mark Twain

--- from a Mark Twain enthusiast in Takoma Park MD