Herbert Spencer,
The Principles of Biology, Volume 2…
(1899)
“ We may, however, fairly draw a parallel between Man and a large carnivore. The Lion, superior in size, and perhaps equal in activity, has a digestive system not proportionately greater; and yet has a higher rate of multiplication than Man. Here the only decided want of parity, besides that of organization, is that of food. Possibly a carnivore gains an advantage in having a surplus nutriment consisting almost wholly of those nitrogenous materials from which the bodies [466] of young ones are mainly formed. ”
