Some books have more impact on me than others. This is one of those books. It is called Our of the Darkness and is the story of Mary Ellen Wilson.
In short, in 1873 there was an American Society for the Prevention of Cruelty to Animals (ASPCA) but not a similar society for children. So you could abuse your child (which was your property) but not your dog.
Mary Ellen Wilson was an abused child but the authorities were unable to act because there was no law against abusing children. So the Society for the Prevention of Cruelty to Animals classified her as a dog so that she could be taken away from her parents and rehomed. She spent a year at the animal shelter.
As a result of this, in 1874 the American Society for the Prevention of Cruelty to Children was created, under the auspices of the ASPCA.