SECT. 2] TO THE RENAISSANCE 107 



2-5. Leonardo da Vinci 



Leonardo was not alone among the artists of the Renaissance in 

 his anatomical interests, for Michael Angelo, Raphael, Diirer, 

 Mantegna, and Verrochio all made dissections in order to increase 

 their knowledge of the human body. But he penetrated more curiously 

 into biology than they did, and he will always remain one of the 

 greatest of biologists, for he first introduced the quantitative outlook. 

 In this he was some four hundred years before his time. 



Leonardo's embryology is contained in the third volume of his 

 notebooks, Quaderni d' Anatomia, published in facsimile by the ad- 

 mirable labours of three Norwegian scholars, Vangensten, Fohnahn 

 and Hopstock, in 191 1. His notebooks are a remarkable, and, indeed, 

 charming miscellany of anatomical drawings, physiological diagrams, 

 architectural and mechanical sketches and notes such as "Shirts, 

 hose, and shoes", "Go and see Messer Andreas", "get coal", "the 

 supreme fool (is the) necromancer, and enchanter". 



His dissections of the pregnant uterus and its membranes are 

 beautifully depicted, as can be seen from the figures which are here 

 reproduced (Plate IV). He was acquainted with amnios and chorion, 

 and he knew that the umbilical cord was composed only of vessels, 

 though he seems to have thought the human placenta was cotyle- 

 donous. There is one drawing which the editors suppose to represent 

 the developing hen's egg, but I do not feel that this ascription is likely. 

 Indeed, Leonardo worked with eggs much less than with mammalian 

 embryos, though there are references to the former. "See how birds 

 are nourished in their eggs", he says in one place, to remind himself, 

 perhaps, of possible experiments, and, elsewhere, "Chickens are 

 hatched by means of the ovens of the fireplace". Again, "Ask the 

 wife of Biagino Crivelli (was she the Lucrezia Crivelli, whose portrait 

 Leonardo painted?) how the capon rears and hatches the eggs of the 

 hen when he is inebriated", a subject recently reopened by Lienhart. 

 "You must first dissect the hatched egg before you show the difference 

 between the human liver in foetus and adult." Leonardo perpetuates 

 a persistent error in the note, "Eggs which have a round form 

 produce males, those which have a long form produce females". 



Concerning the mammalian foetus, he says, "The veins of the 

 child do not ramify in the substance of the uterus of its mother but 

 in the placenta which takes the place of a shirt in the interior of the 



