The introduction within the past few years of satisfactory methods for the indirect transfusion of blood has done much to popularize this procedure. Fortunately the popularity of the procedure rests not solely on a simple and satisfactory technic but also on its therapeutic value in a number of conditions.
It is now generally recognized that isohemolysis and iso-agglutination constitute a possible source of danger in transfusion unless a donor is selected who belongs to the same iso-agglutinin group as that of the patient.
Although many transfusions have been performed between members of different groups without untoward results, there arc a sufficient number of "accidents" on record to remind one that there is an element of danger. That the transfusionist appreciates this is evidenced by the fact that more and more frequently he or his colleague of laboratory habits is taking the trouble to select donors belonging to the same group