In 1892-93, Paul Ehrlich published a series of experiments on the pass
ive transfer of maternal antibody to fetus and newborn that deserve to
be better known. He pointed out the importance of mother's milk to ne
onatal well-being. He was the first to define the difference between a
ctive and passive immunity. He was the first to demonstrate immune eli
mination of antigen and to explain the significance of each phase of t
he kinetics of the anamnestic antibody response. We point out how eleg
ant were these early experiments and how far in advance of their times
. (C) 1996 Academic Press, Inc.