On the timing of the appearance of isohemoagglutinating blood properties in humans

One of the important recent advances in the biological sciences is the teaching of so-called isohemoagglutination, which, as we know, has led to the need to divide people into certain groups. The essence of the isohemoagglutination reaction is that the blood serum of one species of animal glues the erythrocytes of the same species, which depends on the presence in the erythrocytes of agglutinogens (receptors) designated by the letters A and B and in the serum agglutinins designated by the letters a and b. The presence and ratio of agglutinogens and agglutinins determine the blood group identity of an individual.