Page:Popular Science Monthly Volume 58.djvu/577

Rh the chick, as the most available form in which to gel an insight into this process, but he could not extend his observations successfully into periods earlier than about the twenty-four hour stage of development. Two memoirs were written on this subject, both in 1672. Of all Malpighi's work, this has received the least attention from reviewers, but it is, for the time, a very remarkable piece of work. No one can

took over the ten folio plates without being impressed with the extent and accuracy of his observations. His earliest sketches show an open neural groove with an enlargement for the head end, and from this stage onward he carries the development of the chick by sketches to the period of hatching. These sketches are of interest not only to students of embryology, but also to educated people, to see how far