structural:reformatting, information:extraction
Background

The Chinese immigrant workers provided cheap labor and did not use government schools, hospitals, and such because the Chinese migrant population was predominantly healthy male adults. January 1868, the Senate ratified the Burlingame Treaty with China, allowing an unrestricted flow of Chinese into the country. As time passed and more and more Chinese migrants arrived in the United States and California in particular, violence often broke out in cities such as Los Angeles. The North Adams strike of 1870, broken by the replacement of all workers by 75 Chinese men was the trigger that sparked widespread working-class protest across the country, shaped legislative debate in Congress, and helped make Chinese immigration a sustained national issue.