SECT. 3] AND EIGHTEENTH CENTURIES 127 



published in 1623, and twenty-five years were to elapse before 

 Harvey's Exercitations were to be put before the learned world by 

 George Ent. In that time not a few events of importance for the 

 history of embryology took place. 



It will be convenient to speak first of Adrianus Spigelius, whose 

 De Formato Foetu appeared in 1 63 1 . In this book the plates of the 

 gravid uterus which had been prepared some years before for Julius 

 Casserius were now published. They had more influence than 

 Spigelius' text, perhaps, in contributing to the permanent fame of 

 his book. 



He gives for the most part straightforward anatomical descriptions, 

 but he returns to the notion of a cotyledonous placenta in man, and 

 he combats Arantius' opinions about the placenta. Arantius had said 

 that the function of the jecor uterinae was to purify the blood- 

 supply to the foetus, a thoroughly modern idea, but Spigelius opposes 

 this on two grounds, firstly, because the foetus has its own organs 

 for purifying blood, and secondly, because, if Arantius was right, 

 the placenta would always be as red as blood, but this is not the case 

 in such animals as the sheep. Spigelius himself thought that the 

 placenta was for the purpose of preventing severe loss of blood at 

 birth, as would be the case if the embryo was joined to the mother 

 with only one big vessel and not a great many little ones. 



However, Spigelius upholds the view, taken by Rufus of Ephesus 

 and by Vesalius, that the allantois contains the foetal urine, which 

 has to be separated from the amniotic liquid in which the embryo 

 is, because it would corrode the embryonic skin [ne cuti tenellae 

 aliquod damnum urinae acrimonia inferret). This passage is interesting, 

 as showing biochemical rudiments. The first discussion of the 

 vernix caseosa, or sordes, as he calls it, appears in Spigelius, who, 

 however, hazards no guess as to its nature. He is happy in his 

 refutation of Laurentius, who had affirmed that the foetal heart did 

 not beat in utero, and he shows some advance on all previous writers 

 save Arantius in declaring that the umbilical vessels take vital spirits 

 away from the foetal heart, not exclusively to it. He gave, moreover, 

 the first denial of the presence of a nerve in the umbilical cord, and also 

 made the first observation of the occurrence of milk in foetal breasts 

 at birth (for the endocrinological explanation of this see Section 15). 

 Finally, he abolished at last the notion that the meconium in the 

 foetal intestines argued eating in utero on the part of the embryo. 



