Chapter 2, Part 4A - Lieh Tzu

The Keeper of Animals under King Hsüan, of the Chou dynasty, had an assistant named Liang Yang, who was skilled in the management of wild birds and beasts. When he fed them in their park-enclosure, all the animals showed themselves tame and tractable, although they comprised tigers, wolves, eagles and ospreys. Male and female freely propagated their kind, and their numbers multiplied.

The King was afraid lest this man's secret should die with him, and commanded him to impart it to the Keeper.

So Liang Yang appeared before the Keeper and said: 'I am only a humble servant, and have really nothing to impart. I fear his Majesty thinks I am hiding something from you. With regard to my method of feeding tigers, all I have to say is this: when yielded to, they are pleased; when opposed, they are angry. Such is the natural disposition of all living creatures. But neither their pleasure nor their anger is manifested without a cause. Both are really excited by opposition.
~ Lionel Giles translation via Terebess Asia Online ~

Go here to read the introductory post to the chapters of the Book of Lieh Tzu.