33 



7- Summary of the evidence. 



All points towards evolution, no evidence against 

 it. 



Evidence largely circumstantial. 



The succession of horse-like forms, the Planorbis 

 shells of Steinheim, and similar cases afford 

 direct evidence. 



2. Theories of Organic Evolution. 



(OsBORN, From the Greeks to Darwin ; Haeckel, The History 

 of Creation, Vol. i, pp. 70-174; Huxley, Article Evolution, 

 Encyclopaedia Britannica, 9th Ed., Vol. 8, pp. 741-754 ; Pack- 

 ard, Introduction, Riverside Natural History, Vol. i, pp. 

 1-lxii; Darwin, Autobiography, Life and Letters, Vol. i, pp. 

 26-107 ; Wallace, Natural Selection and Tropical Nature, 

 pp. 3-33 and 450-475; Marshall, Lectures on the Darwinian 

 Theory, pp. 1-24, and 200-228.) 



i. The Rise of the Theory of Descent. 



The Greeks. 



Aristotle, etc. 



The " Naturphilosophen." 



Goethe (1790). Metamorphosis of Plants. 



Theory of the skull. 



Treviranus. Adaptation. 



Erasmus Darwin (1795). Effects of new condi- 

 tions. 



Oken. Theory of the skull. " Urschleim." 



ii. The TJieory of Direct Modification. 



Lamarck (1809). Habit and the effect of use and 

 disuse. 



Geoffrey St. Hilaire. Effects of changes in exter- 

 nal conditions. 



The debate of 1830. 



