Although a human embryo possesses so much grace that the untutored
spectator can only admire it in awe, this minute and humble embryo is
still almost unknown to many. For some, it seems to belong to the animal
kingdom only; others see in it man in his most primordial and elementary
aspect. The early life of man thus has become a problem. The development
of man as individual (individual development) begins with fertilization.
The following pages, therefore, concentrate above all on the develop-
ment from the ovum to the embryo. The description given below of the
ontogenesis of the human embryo and its early functions has been
completely documented by our human-embryological collection. Numerous
original pho- tographs and systematically revised drawings were pub-
lished in 1973 under the title Die praenatalen Organsys- teme des
Menschen (The Prenatal Organ Systems of Man); the supplementary
scientific commentaries were published in 1977 in Biokinetics and
Biodynamics of Human Differentiations. A complete series of portrait
illustrations is located at the Science Centre in Toronto, Canada.