GENERAL PRINCIPLES 51 



For some time past I have foimd it more convenient to employ 

 another primary division which is better calculated to give an idea 

 of the beings dealt with. Thus, I distinguish the natural productions 

 comprised in the three aforementioned kingdoms into two main 

 branches : 



1. Organised living bodies ; 



2. Crude bodies without hfe. 



Living beings, such as animals and plants, constitute the first of these 

 two branches of the productions of nature. They possess, as every- 

 one knows, the faculties of ahmentation, development, reproduction, 

 and they are subject to death. 



But what is not known so well, since the fashionable hypotheses 

 do not permit of the belief, is that Uving bodies form for themselves 

 their own substances and secretions, as a result of the activity and 

 functions of their organs and of the mutations wrought in them 

 by organic movements {Hydrogdohgie, p. 112). What is still less 

 known is that the exuviae of these hving bodies give rise to all the 

 composite matters, crude or inorganic, that are to be found in nature, 

 matters of which the various kinds increase in course of time and 

 according to the conditions, by reason of the disintegration which 

 - they imperceptibly imdergo. For this disintegration simpMes them 

 more and more, and after a long period leads to the complete 

 separation of their constituent principles. 



These are the various crude and hfeless matters, both solid and 

 liquid, which compose the second branch of the productions of 

 nature, and most of which are known under the name of minerals. 



It may be said that an immense hiatus exists between crude matters 

 and Hving bodies, and that this hiatus does not permit of a Unear ' 

 arrangement of these two kinds of bodies, nor of any attempt to 

 unite them by a Unk, as has been vainly attempted. 



All known hving bodies are sharply divided into two special kingdoms, 

 based on the essential differences which distinguish animals from 

 plants ; and in spite of what has been said I am convinced that these 

 two kingdoms do not really merge into one another at any point, 

 and consequently that there are no animal-plants, as impUed by the 

 word zoophyte, nor plant-ani mals . — ■ — — ~ __ 



Irritabihty in all or some of their parts is the most general charac- 

 teristic of animals ; it is more general than the faculty of voluntary 

 movements and of feeUng, more even than that of digestion. Now 

 all plants, as I have elsewhere shown, are completely destitute of 

 irritability, not even excepting the so-called sensitive plants nor those 

 which move certain of their parts on being touched or brought into 

 contact with the air. 



