138 FROM THE GREEKS TO DARWIN 



produce many rare and unusual results. The pas- 

 sage from the miracles of nature to those of art is 

 easy; for if nature be once seized in her variations, 

 and the cause be manifest, it will be easy to lead her 

 by art to such deviation as she was first led to by 

 chance ; and not only to that but others, since devia- 

 tions on the one side lead and open the way to others 

 in every direction. 



In the above passage Bacon points out that in 

 artificial selection we take advantage of the 

 chance variations of Nature and accumulate 

 them. In the next passage he points out the pres- 

 ence of transitional forms in Nature between 

 two types (Section 30) : 



In the ninth rank of prerogative instances, we will 

 place bordering instances, which we are also wont to 

 term participants. They are such as exhibit those 

 species of bodies which appear to be composed of two 

 species, or to be the rudiments between one and the 

 other. They may well be classed with the singular or 

 heteroclite instances; for in the whole system of 

 things, they are rare and extraordinary. Yet from 

 their dignity, they must be treated of and classed 

 separately, for they point out admirably the order 

 and constitution of things, and suggest the causes of 

 the number and quality of the more common species 

 in the universe, leading the understanding from that 

 which is, to that which is possible. We have examples 

 of them in moss, which is something between putres- 

 cence and a plant ; in some comets, which hold a place 



