Though it is true that profit should not be the only motive for environmental protection, it is also true that all of the medicines thus far produced by mankind from vertebrate creatures are from a single source: the serum protein of poisonous snakes.
雖說保護生物不應只從實質利益出發，但至今人類所有衍生自脊椎動物的藥劑都得自於同一個來源──也就是毒蛇血清蛋白。