https://embryology.med.unsw.edu.au/embryology/index.php/Historic_Embryology_Papers#Introduction

"Introduction

The linked papers are intended to give some historic background to Embryology. Historically, say pre-20th century, Embryology was not easily separated from Medicine, Anatomy and Physiology and other biological sciences. At the turn of last century the detailed study and attempts to standardise development of human embryos began. Just a few key embryo collections formed the basis of many of the human published literature. The development of animals models were also standardised into developmental stages.

'This page also links to full versions of some of these historic embryology papers. These papers are often included in the Historic links section of each system notes.