130 ZOOLOGICAL PHILOSOPHY 



to carry on and perpetuate the race in the same way, she would have 

 been forced to create directly all races, or rather she would only have 

 been able to create a single race in each organic kingdom, viz. the 

 simplest and most imperfect animals and plants. 



Moreover, if nature had not been able to endow the organising activity 

 with the faculty of gradually increasing the complexity of organisation 

 by accelerating the energy of the movement of the fluids and hence 

 that of organic movement, and if she had not preserved by repro- 

 duction all the progress made in complexity of organisation and 

 all acquired improvements, she would assuredly never have produced 

 that infinitely varied multitude of animals and plants which differ 

 so greatly from one another both in their organisation and in their 

 faculties. 



Finally, she could not create at once the highest faculties of animals, 

 for they are only found in conjunction with highly complex systems 

 of organs : and she had to prepare slowly the methods by which such 

 systems might be brought into existence. 



Thus, in order to estabUsh the state of affairs that we now see in 

 hving bodies, the only direct production that is required from nature, 

 that is to say, the only production that occurs without the co-operation 

 of any organic activity, is in the case of the simplest organised bodies, 

 both of animals and plants ; these she continues to produce every 

 day in the same way at favourable times and places. Now she endows 

 these bodies, which she has herself created, with the faculties of feeding, 

 growing, multiplying, and always preserving the progress made in 

 organisation. She transmits these same faculties to all individuals 

 organically reproduced throughout time and the immense variety of 

 ever-changing conditions. By these means living bodies of all classes 

 and orders have been successively produced/] 



In the study of the natural order of animals, the very definite grada- 

 tion existing in the growing complexity of their organisation and in the 

 number and perfection of their faculties is very far from being a new 

 truth for it was known even to the Greeks ; ^ but they could not set 

 forth its underlying principles and proofs, because they lacked the 

 necessary knowledge. 



Now, in order to facihtate an acquaintance with the principles 

 which have guided me in the exposition that I am about to give, 

 and in order to bring home more closely the gradation observed in 

 the complexity of organisation from the most imperfect animals at 

 the head of the series to the most perfect at the end of it, I have 

 divided into six distinct stages the various modes of organisation 

 recognised throughout the animal scale. 



' See the Voyage du jeune Anacharsis, by J. Barth^lemy, vol. v. pp. 353, 354, 



