On May 2, 1890, the Oklahoma Organic Act was passed officially creating Oklahoma Territory, which initially excluded lands occupied by the Five Civilized Tribes, but reorganized the legal system of Indian Territory, providing for a mechanism to consolidate Oklahoma and Indian Territories.
They used interchangeable parts. This made the mass production possible and caused it to happen.
Douglass portrays the slave traders and agents for slave traders as men auctioning for cattle instead of human beings. The slave traders and agents for slave traders at no point stop to think what they are doing is wrong, instead, it is business as usual and they are eager to acquire misbehaved slaves at steep discounts, much the same as farmers will bid pennies on the dollar for underweight farm animals.