INDEFINITELY FROM THE ORIGINAL TYPE 33 



the weakest the very young, the aged, and the 

 diseased while those that prolong their existence 

 can only be the most perfect in health and vigour 

 those who are best able to obtain food regularly, and 

 avoid their numerous enemies. It is, as we com- 

 menced by remarking, " a struggle for existence," in 

 which the weakest and least perfectly organized 

 must always succumb. 



The Abundance or Rarity of a Species dependent upon 

 its more or less perfect Adaptation to the Con- 

 ditions of Existence. 



It seems evident that what takes place among the 

 individuals of a species must also occur among the 

 several allied species of a group, viz., that those 

 which are best adapted to obtain a regular supply 

 of food, and to defend themselves against the attacks 

 of their enemies and the vicissitudes of the seasons, 

 must necessarily obtain and preserve a superiority 

 in population ; while those species which from some 

 defect of power or organization are the least capa- 

 ble of counteracting the vicissitudes of food-supply, 

 &c., must diminish in numbers, and, in extreme 

 cases, become altogether extinct. Between these ex- 

 tremes the species will present various degrees of 

 capacity for ensuring the means of preserving life ; 

 and it is thus we account for the abundance or rarity 

 of species. Our ignorance will generally prevent us 

 from accurately tracing the effects to their causes; 

 but could we become perfectly acquainted with the 



D 



