THE "GENERAL MORPHOLOGY" 199 



animal and plant worlds and the philosophic 

 exposition of the laws that lie behind these forms. 

 In the eighteenth century, under Linne, there is 

 a period of purely external description and classi- 

 fication. It is succeeded in the first third of the 

 nineteenth century by a triumph of the philosophic 

 treatment of animal and plant forms. This in- 

 creases with Goethe and Lamarck, and grows into 

 the older (and now generally abused) imaginative 

 natural philosophy. Then there is a general 

 reaction ; with Cuvier comes the least philoso- 

 phical of methods, though at the time it is a real 

 advance. While Linne only gave an external 

 description of forms and catalogued them, Cuvier's 

 epoch penetrated to the inner structure, the inner 

 world of forms, and thus rendered great service. 

 The last and greatest workers of the period, 

 Miiller, Schleiden, &c., give the signal for a re- 

 action in the hour of its chief triumph. Haeckel 

 now follows this up as "the element of fact in 

 their ideas." With Darwin he inaugurates the 

 fourth epoch, the triumph of natural philosophy 

 for the second time. But it is now far deeper and 

 clearer; it embodies all the good that preceded, 

 all that Cuvier and his followers have done, without 

 the irresolution of earlier days. Now that we have 

 studied the living form in its innermost structure, 

 as was never done before, in the earliest stages 

 of embryonic development in the ovum and womb, 

 in the past geological periods of the earth's history, 

 we will think over this form, think with all the 

 means at our command, reason, synthesis — even 



