360 THE SURVIVAL OF THE UNLIKE. [xXII. 



well agreed by all naturalists that there are more 

 distinct species or forms upon the earth to-day than 

 there have ever been at any one previous time. We 

 are apt to think that both the animal and vegetable 

 kingdoms have passed the zenith of their develop- 

 ment, because the great number of monstrous forms 

 is now extinct. There were giants in those days. 

 But size or bulk is not a measure of the height of 

 development. Evolution is perfected only when 

 every phase and condition of the external world has 

 some type of life particularly adapted to it ; and 

 inasmuch as new conditions in the physical features 

 of the globe are constantly appearing, there must be 

 a constantly progressing attempt on the part of 

 animals and plants to adapt themselves to these new 

 conditions. The surface of the earth was probably 

 never so varied in physical characters as at the 

 present time, and it is safe to assume, as I have 

 said — particularlx' as such facts as are known sup- 

 port the assumption — that there have never been 

 so many diverse forms of life as at present ; and 

 this differentiation is proceeding as rapidly to-day, 

 probably, as it has at any time in the past. In other 

 words, the only limit to the expansion and evolution 

 of wild- plants is that of the surroundings in which 

 they live ; and as cultivated plants modify them- 

 selves through the same laws, it nnist follow that 

 there is no predetermined limit to their amelioration 

 or improvement, so long as man continues to culti- 

 vate and modify the earth. Every year may witness 

 better varieties, until the plant becomes so unlike 

 its ancestors that its parentage may be lost or un- 

 recognized, and new specific forms, even, may 



