Fifty years ago the field of human embryology was incomplete; prior to that time the anatomy of early human embryos was still unknown, and there was much to be learned about the older stages of human embryonic development. It is now understood that human organs result from step-by-step differentiati[...]
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[...]