ARGUMENT OF DESIGN 105 



fectly efficient and flexible elbow, though probably not 

 at all like the bony structure that had been excised. 



This case reminds one of the fact, a very common 

 feature in Nature, that the same result can be produced 

 by very different 7neans. Thus flight is secured in very 

 different parts of the fore-limb in the extinct Pterodactyle, 

 the existing bat and the bird. 



Similarly, in plants the tendril of a pea closely re- 

 sembles that of the vine ; but while the former is a 

 metamorphosed leaf the latter is homologous with a 

 flowering branch. In saying that Evolution never antici- 

 pates the use of a structure, I repeat, this only applies to 

 its origin. Once formed, heredity tends to preserve it, 

 and continual use to improve it ; we thus obtain organs in 

 every animal and plant now, which are built up during 

 the development in anticipation of their use later on — as 

 the eye in the foetus in total darkness — because the 

 Evolution of any individual being re-capitulates the de- 

 velopment of the race. 



Hence Paley's fourteenth chapter on " Prospective 

 Contrivances," in which he alludes to the eye, must be 

 read in the light of Evolution to understand the real 

 significance of prospective structures. 



Paley has an interesting chapter (xv.) on " Rela- 

 tions". By these he means what are now called " Cor- 

 relations". Thus he says: "The aptness of the jaws 

 and teeth to prepare the food for the stomach is, at least, 

 as manifest as that of the cider-mill to crush the apples 

 for the press. The concoction of the food in the stomach 

 is as necessary for its future use, as the fermentation of 

 the stum in the vat is to the perfection of the liquor, etc." 



" Spallanzani has remarked a circumstantial resem- 

 blance between the stomachs of gallinaceous fowls and 

 the structure of corn-niills. Whilst the two sides of the 



