Turning now to the vegetable kingdom, we find the cornplants—the plants which are best adapted for the food of civilized man—scattered profusely over the Temperate Zone. It is only when man has settled down in a fixed abode, —when he has abandoned his nomadic life and become an agriculturist, attaching himself to a certain locality, —that it is possible for him to rear corn. Corn is not self-sustaining, self-diffusing, like the wild grass. Self-sown, it gradually dwindles away, and finally disappears. "It can only be reared permanently by being sown by man's own hand, and in ground which man's own hand has tilled."

现在来到植物王国，植物王国里最适合人类食用的植物是大量地分布在温带地区的“玉米”。只有当一个人放弃游牧生活在某地安定下来，成为一名专业的农业户并依附于一个特定的地方，这时他才有可能会去种植玉米。玉米不像野草那样可以自给自足、自我繁殖。自我播种只会造成数量逐渐减少，直到最后彻底消失。所以，玉米只能通过人类的双手、在人类亲手耕种的土地上进行种植。

Corn, therefore, a great German botanist has said, precedes all civilization. With it are connected rest, peace, and domestic happiness, of which the wandering savage knows nothing. In order to rear it, nations must take possession of certain lands; and when their existence is thus firmly established, improvements in manners and customs speedily follow. They are no longer inclined for bloody wars, but fight only to defend the fields from which they derive their support.

一位伟大的德国植物学家曾经说过：玉米先于一切文明。与之息息相关的是流浪的野蛮人无法体会的修养、安宁和家庭幸福。因为种植玉米国家必须占有一定面积的土地，当他们在这片土地上执掌大权之时便会去改善礼仪和风俗。他们的战争将不再是为了杀戮，而是为了保卫那片自己赖以生存的土地。

Corn is the food most convenient and most suitable for man in a social state. It is only by the careful cultivation of it that a country becomes capable of permanently supporting a dense population. All other kinds of food are precarious, and cannot be stored up for any length of time: roots and fruits are soon exhausted; the produce of the chase is uncertain, and if hard pressed ceases to yield a supply. In some countries the pith of the sago-palm, the fruit of the bread-fruit tree, the root of the esculent fern, and similar food, supplied spontaneously by nature, serve to maintain a thinly scattered and easily satisfied population; but man in these rude circumstances is invariably found depraved in body and in mind, and hopelessly incapable of bettering his condition. But the cultivation of corn, while it furnishes him with a supply of food for the greater part of the year, imposes upon him certain labours and restraints which have a most beneficial influence upon his character and habits.

玉米是人类生活中最方便、最适合食用的食物。一个国家只有经过精心的培育才有能力持续供养其稠密的人口。而其它种类的食物都易变质，进而不易储存，其根茎和果实会很快枯萎，所以努力不一定会有收获，一旦遇到问题，供给就会停止。在一些国家，山艾树的枝干、面包树上的果实、蕨类植物的根、还有类似的食物，都是大自然为了维持那些稀疏并且容易满足的人类自发供应的。而那些生活在恶劣的环境下的人们常常会身心堕落，对自己无法改变处境无能为力。不过，种植玉米虽然为他们提供了一年里所需的大部分食物，却也同时在他们身上施加了一定的劳动和限制，这对他们性格和习惯的养成有着极为有利的影响。