NATURAL HISTORY. 15 



but what goes naturally into the composition, to make them more perfect 

 as a species of matter ; for, if it [the body not naturally a constituent] 

 united with the combination, it would then alter the species. 



Solution comes the nearest to this idea ; it is a union of two species 

 to make a third ; and, however compounded [the species of matter may 

 be], yet they unite as two species ; which is either by solution or 

 fusion. But all bodies will not fuse and mix, they must have a relation ; 

 perhaps such only [will fuse or mix] as constitute a genus. 



Thus, if we make salts a genus, two species will mix and retain the 

 general property of salt. If we make metals a genus, they mix or fuse, 

 retaining the property of a metal. But species of two different tribes 

 will not fuse, excepting to produce a very different compound, such as 

 glass; and this requires much more violence than the union of two 

 species of the same genus. 



Glass by this means becomes a species, although we know it to be 

 made up of several species. Therefore, in any species of matter, 

 although compounded of a variety of different species which were 

 themselves compounded, the compound from a new combination may 

 become a distinct species. There cannot be in the species of glass now 

 formed a single part as a species of any of the species of which it is 

 composed. For instance, neither calcareous earth, clay, or fixed alkali 

 is to be found [as such] in glass ; they are all decomposed [and the 

 characters lost] on which their species depended. Nor is calcareous 

 earth, clay, iron, or volatile alkali to be found in animal matter, till 

 after this is decomposed, and they then have combined as such ; therefore 

 such is not in animal matter. A piece of animal matter is wholly dis- 

 solvable in a caustic alkali ; but, if that animal substance is analysed, 

 parts of it will not dissolve ; or, if allowed to putrify, parts of it will 

 not dissolve ; therefore it is its combinations that give it the properties 

 of solution. Sulphur is not soluble in water ; but it becomes so when 

 compounded with an alkali. Oil the same. 



A block of marble gives us a figure when cut out ; but we cannot 

 find a figure till cut out : the figure arose from the hand of the statuary. 

 Calcareous earth, therefore, is not in animal matter; but it can be 

 decomposed out of it, which shows calcareous earth to be a compound ; 

 nor is calcareous earth or clay to be found [as such] in glass. However, 

 we have bodies compounded of different species of matter, as above 

 defined, mechanically mixed, having a specific name to be known by, 

 such as bone. A bone is composed of two species of matter — calcareous 

 earth and animal matter. Therefore a bone is not a species of com- 

 bination of matter, but is composed of two [such species]. 



