Where does the phrase “absent treatment” come from and What does absent treatment mean?

In the United States the expression “absent treatment” is used with two differing meanings.

Originally, and properly, it is a term in Christian Science for a treatment by a healer given at the request of and for the benefit of an absent person.

But the term has also acquired a slang sense: treatment such as that shown to a person or an animal not present.

One gives a child, a dog, another person the absent treatment by speaking of him or it as if he were non-existent or not within hearing distance, though actually the speaker knows him to be present and able to hear what is said.