Not the first time I quote The Jungle in HN but...

"During the summer the packing houses were in full activity again, and Jurgis made more money. He did not make so much, however, as he had the previous summer, for the packers took on more hands. There were new men every week, it seemed--it was a regular system; and this number they would keep over to the next slack season, so that every one would have less than ever. Sooner or later, by this plan, they would have all the floating labor of Chicago trained to do their work. And how very cunning a trick was that! The men were to teach new hands, who would some day come and break their strike; and meantime they were kept so poor that they could not prepare for the trial!

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But let no one suppose that this superfluity of employees meant easier work for any one! On the contrary, the speeding-up seemed to be growing more savage all the time; they were continually inventing new devices to crowd the work on--it was for all the world like the thumbscrew of the medieval torture chamber. They would get new pacemakers and pay them more; they would drive the men on with new machinery--it was said that in the hog-killing rooms the speed at which the hogs moved was determined by clockwork, and that it was increased a little every day. In piecework they would reduce the time, requiring the same work in a shorter time, and paying the same wages; and then, after the workers had accustomed themselves to this new speed, they would reduce the rate of payment to correspond with the reduction in time! They had done this so often in the canning establishments that the girls were fairly desperate; their wages had gone down by a full third in the past two years, and a storm of discontent was brewing that was likely to break any day. Only a month after Marija had become a beef-trimmer the canning factory that she had left posted a cut that would divide the girls' earnings almost squarely in half; and so great was the indignation at this that they marched out without even a parley, and organized in the street outside. One of the girls had read somewhere that a red flag was the proper symbol for oppressed workers, and so they mounted one, and paraded all about the yards, yelling with rage. A new union was the result of this outburst, but the impromptu strike went to pieces in three days, owing to the rush of new labor. At the end of it the girl who had carried the red flag went downtown and got a position in a great department store, at a salary of two dollars and a half a week.

Jurgis and Ona heard these stories with dismay, for there was no telling when their own time might come. Once or twice there had been rumors that one of the big houses was going to cut its unskilled men to fifteen cents an hour, and Jurgis knew that if this was done, his turn would come soon. He had learned by this time that Packingtown was really not a number of firms at all, but one great firm, the Beef Trust. And every week the managers of it got together and compared notes, and there was one scale for all the workers in the yards and one standard of efficiency. Jurgis was told that they also fixed the price they would pay for beef on the hoof and the price of all dressed meat in the country; but that was something he did not understand or care about."