166 INTRODUCTION. 



tion,) so is her agency in these (viz. generation or development) 

 either the same or diverse. He who enters on this new and 

 untrodden path, and out of the vast realm of Nature endeavours 

 to find the truth by means of anatomical dissections and expe- 

 riments, is met by such a multitude of facts, and these of 

 so unusual an aspect, that he may find it more difficult to ex- 

 plain and describe to others the things he has seen, than he 

 reckoned it labour to make his observations ; so many things 

 are encountered that require naming ; such is the abundance 

 of matter and the dearth of words. But if he would have re- 

 course to metaphors, and by means of old and familiar terms 

 would make known his ideas concerning the things he has 

 newly discovered, the reader would have little chance of under- 

 standing him better than if they were riddles that were pro- 

 pounded ; and of the thing itself, which he had never seen, 

 he could have no conception. But then, to have recourse 

 to new and unusual terms were less to bring a torch to lighten, 

 than to darken things still more with a cloud : it were to at- 

 tempt an explanation of a matter unknown by one still more 

 unknown, and to impose a greater toil on the reader to under- 

 stand the meaning of words than to comprehend the things 

 themselves. And so it happens that Aristotle is believed by 

 the inexperienced to be obscure in many places ; and on this 

 account, perhaps, Fabricius of Aquapendente rather intended 

 to exhibit the chick in ovo in his figures than to explain its 

 formation in words. 



Wherefore, courteous reader, be not displeased with me, if, 

 in illustrating the history of the egg, and in my account of the 

 generation of the chick, I follow a new plan, and occasionally 

 have recourse to unusual language. Think me not eager for 

 vainglorious fame rather than anxious to lay before you observa- 

 tions that are true, and that are derived immediately from the 

 nature of things. That you may not do me this injustice, I 

 would have you know that I tread in the footsteps of those who 



