CHAPTER VII. 



THE THEORY OF SELECTION (DARWINISM). 



Darwinism (Theory of Selection) and Lamarclcism (Theory of Descent).— 

 The Process of Artificial Breeding.— Selection of the Different Indivi. 

 duals for After-breeding. — The Active Causes of Transmutation. — Change 

 connected with Food, and Transmission by Inheritance connected with 

 Propagation. — Mechanical Nature of these Two Physiological Functions. 

 — The Process of Natural Breeding : Selection in the Struggle for 

 Existence. — Malthus' Theory of Population. — The Proportion between 

 the Numbers of Potential and Actual Individuals of every Species of 

 Organisms. — General Struggle for Existence, or Competition to attain 

 the Necessaries of Life. —Transforming Force of the Struggle for 

 Existence.— Comparison of Natural and Artificial Breeding — Selection 

 in the Life of Man. — Military and Medical Selection. 



It is, properly speaking, not quite correctly that the Theory 

 of Development, with which we are occupied in these pages, 

 is usually called Darwinism. For, as we have seen from 

 the historical sketch in the previous chapters, the most 

 important foundation of the Theory of Development — that 

 is, the Doctrine of Filiation, or Descent — ^had already been 

 distinctly enunciated at the beginning of our century, and 

 had been definitely introduced into science by Lamarck. 

 The portion of the Theory of Development which maintains 

 the common descent of all species of animals and plants from 

 the simplest common original forms might, therefore, in 

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