THE RISE OF EMBRYOLOGY 207 



Bonnet, Haller, and Leibnitz were among its founders. This 

 implication is in part fostered by the circumstance that 

 SwammerdanVs Biblia Nalura, 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 by a 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." (" Qua re pulli stamina in ovo 

 pmexistere, altioremque originem nacta esse fateri convenit, 

 haud dispari ritu, ac in Plantarum ovis.") 



