ON fHE FECULA OF GREEN PLANTS. 275 



(he broken fibres of green plants have never been confounded 

 with that beautiful foft liquid expreffed from their leaves, or 

 with that emulfive product which pafles pure through the 

 (trainer, and which, by its exceffivefioenefs and the brilliancy 

 of its colour, differs fo very much from the herbaceous fila- 

 ments. 



Again, if it were true that the fecula were a body homogene- Its ftate of <fif- 

 ous with the reft of the plant ; if it were poffible to confider it jj'jjjj ]*£** 

 as in no refpect different from the other parts, but by being grinding. . 

 more bruifed, would it not be poffible, by compleating the 

 trituration of the remainder, to convert it alfo into fecula > 

 When a frefli plant is bruifed by the peflle, it is broken fmall ; 

 its texture is deftroyed, but it is not pulverized. 



This crufhing for a few moments, differs too much from a 

 dry pulverization, to admit of any comparifon between the 

 fecula fo produced, and a moiflened powder. When an aque- 

 ous juicy plant, a fedum for example, iscrufhed with a roller 

 on the flab, its expreffed juice will afford fecula. Certainly 

 it is not to the trituration, that a fecula is indebted for its foft- 

 nefs, its finenefs, and the impalpability which diflinguifhes it 

 from powders. It is molecular in its own nature, and is even, 

 perhaps, cryftallized in thofe fibrous cavities where it is de- 

 pofited by vegetation. 



Rouelle afferts, according to Fourcroy, that the feculse The marines of 

 ••i**-i >i <» t» it Rouelle were 



contains a principle fimilar to animal matters, &c. Rouelle not mere a fl* er „ 



does more than that ; little contented with fimple aflfertions, tions, but dear 

 he proves it, not by analogy or equivocal properties, but by a r>om mimerous 

 fucceffion of convincing fads, by approximations which have facts, 

 been univerfally admitted, becaufe they combine together the 

 moft prominent characters which were then known, or are 

 even yet known, to exift in animal fubftances. Whence 

 otherwife could Rouelle have drawn his analogies, to enable 

 him to compare, as he does, the green fecula with the gluten 

 of wheat ? In fact, what is there in the common appearance 

 of thefe two products that can lead to the comparifon ? Their 

 points of comparifon muft be fought for in their compofition, 

 in their chemical properties, and this was done by that inde- 

 fatigable chemift. Thefe are approximations drawn from 

 analyfis which ferve as the bafis of the Memoir he has written 

 on the green feculoe, and of which there is no mention in the w &icb. Fourcroy 

 Syftem of Chemical Knowledge; doubtlefs becaufe in the 



T 2 opinion - 



