"The day may come when the rest of the animal creation may acquire those rights which never could have been witholden from them but by the hand of tyranny.
"It may one day come to be recognized that the number of the legs, the villosity of the skin, or the termination of the os sacrum are reasons equally insufficient for abandoning a sensitive being to the same fate.
"What else is it that should trace the insuperable
line? Is it the faculty of reason or perhaps the faculty of
discourse? But a full-grown horse or dog is beyond comparison a more
rational, as well as more conversable animal, than an infant of a day or a
week or even a month old. But suppose they were otherwise, what would
it avail? The question is not, Can they reason?,
nor Can they talk? but, Can they suffer? Why should
the law refuse its protection to any sensitive being? The time will
come when humanity will extend its mantle over everything which breathes..."
~ From: Principles of Morals and Legislation