In the course of my reading I had come across a case where , many years ago ,some hunters on our Great Plains organized a buffalo hunt for the entertainment of an English earl( 伯爵 ) and to provide some fresh meat for his use. They had charming sport. They killed seventy-two of those great animals; and ate part of one of them and left the seventy-one to rot. In order to determine the difference between an anaconda and an earl, I had seven lambs turned into the anaconda’s cage. The grateful snake immediately crushed one of them and swallowed it, then lay back satisfied. It showed no further interest in the lambs, and no inclination to harm them. I tried this experiment with other anacondas; always with the same result. The fact stood proven that the difference between an earl and an anaconda is that the earl is cruel and the anaconda isn’t ; and the earl wantonly( 肆无忌惮地 ) destroyed what he has no use for , but the anaconda doesn’t . This seemed to suggest that the anaconda was not descended from the earl. It also seemed to suggest that the earl was descended from the anaconda, and had lost a good deal in the transition. I was aware that many men who have accumulated more money than they can ever use have shown a hunger for more, and have not hesitated to cheat the ignorant and the helpless out of their poor serving in order to partially satisfy that appetite. I furnished a hundred different kinds of wild and domestic animals the opportunity to accumulate vast stores of food but none of them would do it .The squirrels and bees and certain birds made accumulations, but stopped when they gathered a winter’s supply, and could not be persuaded to add to it either honestly or by trickery. These experiments convinced me that there is this difference between man and the higher animals: he is greedy, they are not. In the course of my experiments I convinced myself that among the animals man is only one that harbors insults and injuries, broods over( 默默沉思 )them, waits till a chance offers, then takes revenge, The passion of revenge is unknown to the higher animals.