The spirit in which he went about that work, the results of which have put the world eternally in his debt, is fairly indicated by a memorandum written in his early forties and never
intended for publicity: «Believing that I was born for the service of mankind, and regarding the care of the commonwealth as a kind of common property, which, like the air and the
water, belongs to everybody, I set myself to consider in what way mankind might best be served, and what service I was myself best fitted by
nature to perform.»
I think Amy's assertion about land mammals is
intended to demonstrate the cognitive dissonance suffered by some natural birth advocates that promote
water birth, not as an argument that we should eschew it and follow
nature.