xxxii INTRODUCTION 



philosophy was far behind that taught by many of his greater 

 contemporaries and forerunners. 



I The method by which Lamarck believed evolution to have 

 \been brought about was by the inheritance of minute 

 1 variations : and he was altogether opposed to any belief in 

 Ithose larger variations which we now call mutations. " If 

 the procedure of nature is attentively examined," he writes, 

 " it will be seen that in creating or giving existence to her I 

 productions, she has never acted suddenly or by a single j 

 leap, but has always worked by degrees towards a gradual 

 and imperceptible development." For the explanation of 

 this behef we have to remember that the current notions of 

 his time were of the catastrophic t3rpe. Species were sup- 

 posed to have been individually created by single and 

 instantaneous acts : the surface of the earth was likewise 

 regarded as having been exposed to a series of violent 

 catastrophes, so that the changes which have visibly enough 

 come over it were due, not to slow and gradual processes, 

 but to a succession of sudden large breaks. 



Now those who upheld the standard of uniformitarianism 

 were inclined to state their position in the most uncom- 

 promising way. They adduced such maxims as " Natura 

 non facit saltum," and endeavoured to show that evolution 

 proceeded invariably by minute and imperceptible gradations. 

 It is possible that they went too far : nevertheless, we have 

 to remember that they never envisaged the modern problem 

 of the mutation theory. For them the antithesis was 

 between catastrophic transformations and transformations 

 by imperceptible gradations. Even should the doctrine 

 of Bateson and De Vries be well founded, the evolutionists 

 of a century ago must be held as its ancestors in a direct 

 line. 



In the same way that uniformitarianism, though a true 

 principle, was not propounded in precisely correct terms, so 

 also transformism tended to be asserted in somewhat too 

 extreme a fashion. By reaction against the doctrine that 

 species were immutable, the evolutionists of the time under 



