SMITH, Kathleen: J. P. Hill and Katherine Watson’s studies of neural tube and neural crest development in marsupials.

In the early part of the 20th century, James P. Hill and Katherine Watson initiated a study of the early development of the nervous system in marsupials. In this study, they used Hill’s superb collection of embryos from a variety of marsupial families include Peramelidae, Dasyuridae, and Macropodidae. Soon after the initial study, Watson discovered that in marsupials a large mass of cells migrates from the anterior part of the neural plate, and contributes to the mesenchyme of the facial region. These cells were, of course, neural crest. However, at this time, few embryologists accepted the possibility that cells derived from the ectoderm could contribute to mesodermal tissues. Except for a presentation by Hill in 1920 of this work at a meeting of the Anatomical Society of Great Britain and Ireland, and of the posthumous publication of this talk in 1958, none of this work has been published. In recent years, it has been claimed that Hill prevented the publication of this work because of his devotion to the germ layer theory. After Hill’s death, the material, along with Hill’s embryological collection, was donated to the Hubrecht Comparative Embryology Collection at the Netherlands Institute of Developmental Biology, in Utrecht, the Netherlands. In this talk, I present the major findings of their work, contained in over 400 pages of notes, drafts and illustrations made by Watson and Hill between 1919 and approximately 1946. Further, I outline major features of Watson and Hill’s biographies that may in part explain the delay in publication of this work. I argue that it is clear that Hill accepted the contribution of neural crest cells to the ectomesenchyme, and that the delay in publication is likely to be due to a number of factors.