LORD & AC ON TO CHARLES DARWIN. 63 



exponent of the views of others than an originator 

 of any theory of his own. 



Species and Varieties. 



The difficulty of distinguishing species from 

 varieties a difficulty with which all botanists and 

 zoologists are familiar, and one which augments with 

 the progress of knowledge of the fauna and flora of 

 the world and the almost perfect gradations charac- 

 terizing the forms of certain groups of animals and 

 plants, contributed more than anything else towards 

 impelling naturalists from the time of Lamarck to 

 accept the doctrine that species are derived from 

 one another by a process of development. 



Observations similar to those made by Lamarck 

 and other naturalists, led the Rev. W. Herbert, of 

 England, to declare, in 1837, that " Horticultural ex- 

 periments have established, beyond the possibility 

 of refutation, that botanical species are only a higher 

 and more permanent class of varieties." He enter- 

 tained the same view regarding animals, and believed 

 "that single species of each genus were created in 

 an originally highly plastic condition, and that these 

 by intercrossing and by variation have produced all 

 our existing species." 



In 1844 appeared the famous " Vestiges of Crea- 

 tion," an anonymous work by Robert Chambers. 

 This work created a profound sensation at the time, 

 and although lacking in scientific accuracy in many 

 points, and advocating theories that have long since 

 been demolished, it passed through many editions 

 and commanded a wide circle of readers. In Great 



