Paul Ehrlich: the founding of pediatric immunology.

In 1892-93, Paul Ehrlich published a series of experiments on the passive transfer of maternal antibody to fetus and newborn that deserve to be better known. He pointed out the importance of mother's milk to neonatal well-being. He was the first to define the difference between active and passive immunity. He was the first to demonstrate immune elimination of antigen and to explain the significance of each phase of the kinetics of the anamnestic antibody response. We point out how elegant were these early experiments and how far in advance of their times.