x CONTENTS 



competent to produce the present condition of things, but must 

 inevitably have done so. 



The Doctrine of Evolution : its gradual spread. Herbert Spencer s 

 article in the " Leader " 1852, Recognition of descent of species 

 from one another by modification, but inability to point out the 

 causes of such modification. 



THE THEORY OF NATURAL SELECTION. 



Charles Darwin, 1809 — 1882. 



Alfred Russel Wallace, 1823 — 



General sketch of the life and work of Darwin and Wallace. 

 Simultaneous announcement of the Theory of Natural Selection 

 at the meeting of the Linnean Society on July 1, 1858. 



LECTURE II. (Pp. 27-5 



ARTIFICIAL AND NATURAL SELECTION. 



The breeding of domestic animals by Artificial Selection. 



The characters of the principal breeds of domestic pigeons : pouter, 

 carrier, barb, fantail, turbit, tumbler. 



Evidence in support of the descent of the various breeds of domes- 

 tic pigeons from the wild rock-pigeon, Columba livia. 



The principles and practice of breeding animals. Variation with 

 heredity. The power and efficiency of Artificial Selection. The 

 breeding of horses, cattle, sheep, dogs, fowl, &c. 



NATURAL SELECTION. 



There are in nature causes which act in much the same way as man 

 acts, when selecting artificially the best animals for breeding 

 purposes ; causes which must lead to structural modifications. 



The tendency to rapid increase of numbers. Rapid multiplication 

 of rabbits in Australia. 



The causes tending to keep the numbers stationary on the average. 

 Effect of removal of any check to increase. 



The struggle for existence applies to all animals and at all times. 

 Competition is keenest between the most closely similar forms. 

 Competition amongst men. 



Variation . its universal occurrence. Variation occurs in all direc- 

 tions, and affects all organs and parts. The importance of 

 small variations in the breeding of domestic animals. 



