Ueber Entwicklungsgeschichte der Thiere. 2 vols.

Baer, the founder of modern embryology, definitely established the “germ-layer theory”, discovered the notochord and the human ovum, and postulated the law of corresponding stages in embryonic development. With Cuvier he is the founder of modern morphology. Later in his life he devoted much time to the study of anthropology. Part of vol. 1 was published in No. 599. In response to demands by subscribers to the treatise, the publishers issued vol. 2 in incomplete form in 1837. The conclusion to vol. 2, sometimes called volume 3, was edited by Ludwig Stieda and published 12 years after von Baer’s death.