THE RISE OF EMBRYOLOGY 207 
Bonnet, Haller, and Leibnitz wereamong its founders. This 
implication is in part fostered by the circumstance that 
Swammerdam’s Biblia Nature, which contains the germ of 
the theory, was not published until 1737—more than half a 
century after his death—although the observations for it were 
completed before Malpighi’s first paper on embryology was 
published in 1672. While it is well to bear in mind that date 
of publication, rather than date of observation, is accepted 
as establishing the period of emergence of ideas, there were 
other men, as Malpighi and Leeuwenhoek, contemporaries 
of Swammerdam, who published in the seventeenth century 
the basis for this theory. 
Malpighi supposed (1672) the rudiment of the embryo to 
pre-exist within the hen’s egg, because he observed evidences 
of organization in the unincubated egg. This was in the 
heat of the Italian summer (in July and August, as he him- 
self records), and Dareste suggests that the developmental 
changes had gone forward to a considerable degree before 
Malpighi opened the eggs. Be this as it may, the imperfec- 
tion of his instruments and technique would have made it 
very difficult to see anything definitely in stages under 
twenty-four hours. 
In reference to his observations, he says that in the unin- 
cubated egg he saw a small embryo enclosed in a sac which 
he subjected to the rays of the sun. ‘Frequently I opened 
the sac with the point of a needle, so that the animals con- 
tained within might be brought to the light, nevertheless to 
no purpose; for the individuals were so jelly-like and so very 
small that they were lacerated bya light stroke. Therefore, 
it is right to confess that the beginnings of the chick pre-exist 
in the egg, and have reached a higher development in no other 
way than in the eggs of plants.” (‘‘Quare pull stamina in ovo 
preexistere, altiorémque originem nacta esse fateri convenit, 
haud dispari ritu, ac in Plantarum ovis.’’) 
