THE STRUGGLE FOR EXISTENCE. 49 



A time of final equilibrium, a peace which is ap- 

 parent, not real, and changed with a breath ; rhythm 

 of adaptation. 



No permanence in this ; present conditions but 

 phases of change. Small events change current of 

 affairs. Seasons return, or appear to return, because 

 conditions return. Conditions never return in the 

 world of life. 



When increase ceases, extinction may begin. 



Disappearance of Species. Auk, Labrador duck, sea 

 cow, passenger pigeon, buffalo. Dependence of species 

 on species. Clover dependent on cats ; on New Zea- 

 land bees ; seal, salmon, and otter ; carp and canvas- 

 backs. 



Types hardened or sifted by struggle as against 

 others. " The Yankee in King Arthur's Court " ; " The. 

 Scheezicks" ; "The Man Who Would Be King." 



Substitution of Species. Rats, flies, and water-cress 

 in New Zealand. Rabbits, foxes, thistles, in Australia. 



Domestic Animals and Plants. Species or races made 

 by man. Man changes conditions, and Nature makes 

 these forms. Races of dogs, sheep, horses, pigeons, 

 fruit. Goodale's observation. Along lines of variation 

 anything possible with time and patience. Pigeons : 

 pouter, carrier, fantail, tumbler, frill-back, owl. Each 

 fancier sure of separate origin of the variety he rears. 

 Somerville ; sheep chalked on a wall. Youatt ; ma- 

 gician's wand. Species never return unless condi- 

 tions return. Solid-hoofed pigs ; Ancon sheep. Porto 

 Santo rabbits. Power of time, by addition of incre- 

 ment of many generations. Species never return to 

 original type unless all conditions return. 



