a history of embryology

according already amniotic ancient animals appears argument Aristotle become beginning biology birds blood body called cause century chapter chemical chick chicken comparative conception concerning contains described discussion early embryo embryology epigenesis exist experiments Fabricius fact female final foetal foetus force formation formed give given grow growth Haller Harvey Harvey's hatched head heart heat human idea Illustrations important incubation interesting John kind knowledge later less liquid living London male material matter means membrane mentioned mother namely nature Needham nourishment nutrition observations opinion organs origin Paris passage perfect perhaps period placenta present principle produced published question reason reference regarded relation remarkable says seed seems seen semen soul speculation substance theory things thought treatise umbilical uterus veins vessels whole writings yolk