CONTENTS 



PAGE 



new Resources discovered ; Domestication has caused Animals 

 to vary in all parts of their Organism, from Weight of Brain 

 to Length of Digestive Tract. Third Group of Facts: 

 Cultivation of Plants ; its Influence ; the Departure from 

 the original Wild Type ; Variation in all parts of the Plants 

 from Roots to Flowers ; Numerous Varieties of the commonly- 

 cultivated Vegetables. Fourth Group of Facts : Influence of 

 Environment on Structure ; Closeness of Agreement between 

 Environment and Organism ; Beudant and Raulin's Experi- 

 ments ; the Author's Experiments ; Dareste and Teratogeny ; 

 Pouchet, Yung ; Facts and Experiments ; Pierre Lesage ; 

 Schmankevitsch ; Weismann's Criticisms 156 



LECTURE V 



Experimental Evolution based on the four preceding Groups of 

 Facts. These Facts illustrate at the same time its Methods, 

 which are : Change of Environment ; Use and Disuse ; 

 Natural Selection ; Sexual Selection ; and Physiological 

 Selection. These Factors of Evolution must all be subjected 

 to Experimental Test in order to show what they can Effect. 

 What is wanted : A Direct Proof, which all may Perceive and 

 Touch, of one Species (or Form) giving Birth to another 

 more or less Different, and Permanent. Numerous Accessory 

 Problems to be Investigated at the same time. Scientific 

 and Practical Import of this line of Investigation. Require- 

 ments : Farm and Laboratory ; Animals and Plants ; Time ; 

 Experiments must be able to last 20, 50, 100 Years or more. 

 This Experimental Investigation must and shall be performed. 

 But who is to begin ? . 226 







INDEX 261 



