INTRODUCTION. 



nation of this paragraph. When we wish to arrange a 

 system j or, which is the same thing, when we wish to deter- 

 mine the natural order of bodies ; we must first find a princi- 

 ple on which to ground that determination. But this prin- 

 ciple should be taken from the nature of the bodies, as being 

 the consequence of it j and since it is by that we determine 

 in what degree these bodies are similar or unlike, it should 

 show equally the principle of their difference. We perceive 

 in these bodies certain resemblances which are the foundation 

 of their differences, and as these several resemblances are 

 more or less allied or varied, so it is with the bodies which 

 produce them ; this then is the only principle on which we 

 can determine the class or order of these natural bodies. It 

 remains now to show where relations are found in natural 

 bodies 5 but here we find a difference between them, for they 

 are divided into two principal species, these relations in one 

 consisting in the conformation, and those of the other in the 

 composition; the first comprising animals and vegetables, 

 as the second embraces meteors and the mineral kingdom. 

 It is true that, as being natural bodies, they are at the same 

 time aggregated and composed j but the first are formed of 

 parts differing one from another, and which we cMl organs, 

 which constitute their relations ; the last, on the contrary, 

 are simple, or formed of similar parts, and consequently can 

 have no relationship in their aggregation. Now, as they 

 nevertheless really differ, that is to say, they have different 

 characters, we must endeavour to recover them in some man- 

 ner ; and, as I have already said, this can be only by their 

 composition. As a proof of which, when I have divided into 

 as small parts as possible, a substance of one of the first two 

 kingdoms, for example a plant, I cannot affirm that each 

 separate part is the same plant 5 because not any of these 

 parts have the same relationship as in their state of aggrega- 

 tion, that is to say, in their entire plant, and that it is this 

 total which forms this or that plant. It is then in this re- 

 union that we must show the character of this plant, since it 

 is destroyed by the division. On the contrary, I can divide 



