Early transfusion was based on the notion that giving blood would help balance the humors (4,5). On June 15, 1667, Jean Davis replaced part of a patient's blood with sheep's blood though the patient died and Dr. Davis was subsequently accused of murder. Transfusion was set back until the 19th century, well before blood typing was understood.
2) Galen's Four Humors
4) Bleeding and Transfusion