210 FROM THE GREEKS TO DARWIN 



the blades of grass. Of these and similar acquisi- 

 tions he says: 



All which seem to have been gradually produced 

 during many generations hy the perpetual endeavour 

 of the creatures to supply the want of food, and to 

 have been delivered to their posterity with constant 

 improvement of them for the purposes required, 

 [Italics my own.] 



The idea of protective coloring he thus defi- 

 nitely unfolds: "There are organs developed for 

 protective purposes, diversifying both the form 

 and colour of the body for concealment and for 

 combat." 



He closes his long argument by pointing out 

 the close descending gradations in Nature from 

 the higher to the lower forms, and the substan- 

 tial similarity between the animal and vegetable 

 kingdoms in their modes of generation or repro- 

 duction, and concludes as follows: 



From thus . . . considering in how minute a por- 

 tion of time many of the changes of animals above 

 described have been produced; would it be too bold 

 to imagine, that in the great length of time, since the 

 earth began to exist, perhaps millions of ages before 

 the commencement of the history of mankind, . . . 

 that all warm-blooded animals have arisen from one 

 living filament, which the great First Cause en- 

 dued with animality, with the power of acquiring 



