21* 



He lecufes the 

 ancient chemifts 

 of inaccuracy, 



which is not 

 well founded. 



The fecula was 

 never confound- 

 ed with fibrous 

 matter. 



ON THE FECJJLA OF GREEN PLANTS. 



given indifferently to the fibrous matter contained in the juice 

 of plants, and to the ftarch, has induced chemifts to confider 

 the latter as part of the refidue of folid vegetable fnbftances, 

 and there is reafon to think that it was only by analogy, or 

 perhaps by certain equivocal properties, that Rouelle be- 

 lieved the green matter contained any of the glutinous fub- 

 ftances ; fubfequent experiments at Ieaft, and fuch as I have 

 many times repeated on coloured fecula?, have not yielded 

 me the confirmation of this affertion, nor has any thing been 

 afcertained with certainty, that the gluten is one of the prin- 

 ciples of this latter fecula." 



The name of fecula, fays Fourcroy, being given indifferently 

 to the fibrous matter contained in the juic» of plants, and to 

 the ftarch, has induced chemifts to confider the latter as part 

 of the refidue of folid vegetable fubftances, and there is rea- 

 fon, &c. 



I fhall firft notice that this opinion is not correct. For ex- 

 ample, the chemifts of the prefent day will never agree with 

 Fourcroy, that the confufion arifing from the improper appli- 

 cation of terms, of which later chemifts have juftly complained, 

 has, by a neceffary confequence, produced inaccuracy in thofe 

 who have preceded us. Our mafters, it is true, gave bad names 

 to things, but they did not confound them more than we do. 



Even at the time when every vegetable precipitate was 

 called a fecula, the fimilarity of terms never milled them fo 

 far as to caufe them to confound the ftarch with the refidue of 

 the folid parts of plants. Firft, we are not acquainted with 

 any refidue of this defcription, to which chemifts ca» reafon- 

 ably compare it; and fecondly, if any of them did take the 

 green fecula for a refidue, there was not one of them who 

 did not perfectly know the difference between this fecula 

 or refidue and ftarch ; and as no fuch confufion is to be found 

 in their works, the reproach is unjuft ; we need only look into 

 thofe of Rouelle, Macquer, Baume, Sage, Parmentier, &c. 

 to be convinced that the term of fecula has never mifled thefe 

 authors into aflimilations fo difcreditable to their judgment, as 

 to place in the fame rank the green fecula, the refidue of the 

 folid parts, and the ftarch. 



We will now proceed to the green fecula?, and affirm, that 

 in the laboratories in pharmacy, and ftill lefs in the hands of a 

 chemift fo celebrated for accuracy of obfervation as Rouelle, 



the 



