HISTORY OF THE THEORY OF EVOLUTION 19 



to all civilised nations, which thereby enabled men 

 to speak of animals and groups of animals with 

 exactness and certainty. The difficulties of framing 

 definitions based on facts, of which equally competent 

 men took widely different views, led to the con- 

 sideration of the question — Are species fixed or 

 mutable? Buffon, Goethe, Lamarck, St. Hilaire, 

 and Herbert Spencer are perhaps the most famous 

 names among the supporters of Evolution. Lamarck 

 and St. Hilaire are specially noteworthy, as they 

 recognised the necessity of explaining the causes of 

 the modification, and attempted, though with very 

 partial success, to supply the explanation. Among 

 the opponents of Evolution, Cuvier was by far the 

 ablest. 



The question first became a prominent one about 

 the commencement of the present century. It was 

 hinted at earlier by Buffon, but first obtained definite 

 expression from Lamarck in 1801, and in more detail 

 in the "Philosophic Zoologique," published in 1809. 



It is very commonly assumed that the doctrine 

 that animals are not immutable, or the doctrine of 

 Evolution, is of very recent origin, and that for it 

 we are indebted to Darwin. Nothing can be more 

 erroneous, for, as we have seen above, not only was 

 it very clearly and emphatically maintained by 

 several writers at the commencement of the present 

 century, or the conclusion of the last, but the idea 

 is found stated more or less explicitly by Aristotle 

 over 2000 years ago. 



The "Doctrine of Evolution" teaches that there 

 is a relationship between the animals of successive 



