Edgar Rice Burroughs Quote

Had there been no other personal attribute to influence the final outcome, Tarzan of the Apes, the young Lord Greystoke, would have died as he had lived — an unknown savage beast in equatorial Africa.
But there was that which had raised him far above his fellows of the jungle — that little spark which spells the whole vast difference between man and brute — Reason. This it was which saved him from death beneath the iron muscles and tearing fangs of Terkoz.

Ch. 12 : Man's Reason - Tarzan of the Apes (1912)