Although the inheritance, according to definite mendelian principles, of group-specific substances in human blood has been known for ten years, the application of this information to medicolegal questions has not yet been made. It is my object in the present paper to present the possibilities of this practical application and to define the instances in which it can be used.
The term iso-agglutination describes the agglutination of red blood cells by contact with blood serum derived from another individual of the same species. Landsteiner, in 1901, showed that this is a normal phenomenon in all human blood, and reduced its occurrence to a definite law. With regard to the behavior of their serum and red blood cells, all human beings, without regard to race, sex or state of health, fall into one of three groups. In the first group the red cells are not agglutinable by any other human serum,