CHAPTER IX. 



OF THE FACULTIES PECULIAR TO CERTAIN LIVING BODIES. 



Just as there are faculties common to all bodies that enjoy life, as I 

 have shown in the preceding chapter, so too we find in certain living 

 bodies faculties peculiar to themselves and not shared by the rest. 



We are now confronted with a circumstance of capital importance, 

 to Avhich the utmost attention should be paid if further progress is to be 

 made in natural science ; it is this. 



It is quite clear that both animal and vegetable organisation have, 

 as a result of the power of life, worked out their own advancing com- 

 plexity, beginning from that which was the simplest and going on to 

 that which presents the highest complexity, the greatest number of 

 organs, and the most numerous faculties ; it is also quite clear that 

 every special organ and the faculty based on it, once obtained, must 

 continue to exist in all living bodies which come after those which 

 possess it in the natural order, unless some abortion causes its dis- 

 appearance. But before the animal or plant which was the first to 

 obtain this organ, it would be vain to seek either the organ or its faculty 

 among simpler and less perfect living bodies ; for neither the organ 

 nor its faculty would be found. If this were otherwise, then all known 

 faculties would be common to all living bodies ; every organ would be 

 present in each one of these bodies, and there would be no progress 

 in complexity of organisation. 



It is, on the contrary, well established that organisation exhibits an 

 obvious progress in complexity, and that all living bodies do not possess 

 the same organs. Now I propose to show that, from want of sufficient 

 study of nature's order in her productions and of the remarkable 

 progress that occurs in complexity of organisation, naturalists have 

 made altogether fruitless attempts to trace in certain classes, both of 

 animals and plants, organs and faculties which could not possibly be 

 there. 



We must then first determine the point in the natural order, say of 



