VEGETABLE STRUCTURE. 
39 
regular growth ; for that muft depend on veffels. Plants having veflels, 
may have a regular growth ; for it is the effedt of their proper office : but 
wanting nerves, they cannot leel ; that being the quality of nerve alone. 
Animals which have nutritive veffids and nerves, grow and feel j thefe be- 
ing the offices of thofe two fyflems. 
This ehabliffiment of the charadleriftick of Animals in a fvflem of 
nerves will appear lingular; for every opinion does fo when it is fi/lf pro- 
pofed : but, probably, more obfervation will the more confirm it : all I have 
been able to obferve, has this plain tendency ; and certainly there wants 
fuch a fixed mark for the feparate charadter. Nature made the mineral, 
vegetable, and animal world difiindt ; and nothing is diftindt except it have 
fome fuch invariable charadler of the diftindfion : this has been unluckily 
traced hitherto, and even the greatefl: naturallfis have endeavoured to find 
it in charadters that were equivocal : many minerals have a regular form ; 
and there are Plants which are not fixed to one place ; and animals which 
are : yet thefe have been the ufual marks of feparation. Anatomy teaches 
us difiindfly what the nerves are ; and by that lyfiem we feparate the two 
greater clafles : the minerals are fufficiently diftinguiflied from both, in their 
nature and obvious appearance. Nature makes all her changes by minute gra- 
dations, nor is there any great gap in the univerfal chain. Thus the Senfitive 
Plant approaches towards the animal kind, in motion ; and the Dufty Byf- 
fus fcarce enjoys an apparent difhindlion from the earth on which it grows : 
yet with a fixed charadter once eftabliffied, there can be no difficulty or 
confufion. 
Vegetables are placed by Nature in a middle date, between the mi- 
neral and the animal claffes : fuperior to the minerals, in having organized 
bodies ; inferior to the animal kinds, in wanting a nervous fyfiem. They 
are capable of growth, but below fenfation. 
CHAP. II. 
Of the Constituent Matter of Vegetables. 
W E are accufiomed to confider the Matter of A^egetable and Animal 
Bodies as difiindt ; but all may be reduced by fermentation to the 
fame fubfiance. This fermentation is a plain and regular operation of na- 
ture ; which always takes place, in vegetable and animal bodies, when they 
ceafe to live and grow j and needs no human art to help it. A piece of 
the 
