The influence of Karl Ernst von Baer's embryology, 1828-1859: a reappraisal in light of Richard Owen's and William B. Carpenter's "palaeontological application of 'Von Baer's Law".

Abstract

Historians of biology are virtually unanimous in their praise of the nineteenth-century German embryologist Karl Ernst von Baer (1792-1876). Nordenskiold awards von Baer "first place among the creators of modern embryology," and Singer credits him with having introd4ced "the definitive modern stage in the study of development." Similarly, Jane Oppenheimer says that von Baer "brought embryology into its full dignity as a science" and that embryologists today still live by von Baer's laws of development.' Almost as widespread as this estimation of von Baer's greatness, however, is the assumption, which I believe to be erroneous, that his embryological theory had but little influence during his own lifetime. The laws that von Baer stated in 1828 in direct opposition to the theory of recapitulation of Meckel, Serres, Oken, and others, it is said, failed to dislodge this older theory from its prominent position in the embryological thought of his contemporaries. This opinion is most clearly stated by William Coleman in his Biology in the Nineteenth Century: "Whether fully articulated or merely repeated pro forna, the recapitulation doctrine reappeared after 1830 with familiar regularity in most treatises on anatomy, embryology, and the general principles of natural history . . . [V]on Baer's widely read refutation had limited enduring effect."2 I believe that von Baer's theory was considerably more influential than the preceding quotation suggests. It was not only widely read but