The desire of "civilized" humanity for material goods is insatiable. Man is also the only animal to have developed commerce. Ivory has been a common raw material since the earliest days of markets, and its consumption has grown continuously.
「開化」後的人類，物質慾望探不到極限，又是動物世界裡唯一發明出商業拓展的物種，市場一經開創，象牙成為普遍的加工原料，消耗量跟著無止境擴大。