If a person from 1700 asked you your job, would they understand your answer, and if not, how would you explain it to them?

Is your dad actually your dad, or is he your brother? Well my job uses your blood to find out these questions and more. We mix your blood with glowing ingredients, and compare the illuminated patterns that we see when we shine light on it with those of your family members, as well as compared to a rough reference mishmash of all blood we've collected so far.

Can you offer me your arm, please?