202 BIOLOGY AND ITS MAKERS 



nate in eggs, and it was directed against certain contrary 

 medical theories of the time. 



The first edition of his Generations Animalium, London, 

 1651, is provided with an allegorical frontispiece embodying 

 this idea. As shown in Fig. 60, it represents Jove on a 

 pedestal, uncovering a round box, or ovum, bearing the 

 inscription "ex ovo omnia" and from the box issue all forms 

 of living creatures, including also man. 



Malpighi. The observer in embryology who looms into 

 prominence between Harvey and Wolff is Malpighi. He 

 supplied what was greatly needed at the time an illustrated 

 account of the actual stages in the development of the chick 

 from the end of the first day to hatching, shorn of verbose 

 references and speculations. 



His observations on development are in two separate 

 memoirs, both sent to the Royal Society in 1672, and pub- 

 lished by the Society in Latin, under the titles De Formatione 

 Pulli in Ovo and De Ovo Incubato. The two taken together 

 are illustrated by twelve plates containing eighty-six figures, 

 and the twenty-two quarto pages of text are nearly all devoted 

 to descriptions, a marked contrast to the 350 pages of Harvey 

 unprovided with illustrations. 



His pictures, although not correct in all particulars, repre- 

 sent what he was able to see, and are very remarkable for 

 the age in which they were made, and considering the instru- 

 ments of observation at his command. They show successive 

 stages from the time the embryo is first outlined, and, taken 

 in their entirety, they cover a wide range of stages. 



His observations on the development of the heart, com- 

 prising twenty figures, are the most complete. He clearly 

 illustrates the aortic arches, those transitory structures of 

 such great interest as showing a phase in ancestral history. 



He was also the first to show by pictures the formation of 

 the head-fold and the neural groove, as well as the brain- 



