On the Fecula of Green Plants. 1 £?3 



the course of my obsenations on the System of Chemical 

 Knoulcdge. 



To save the reader from the trouble of recurring to that 

 work, I shall copy the passage where the author collects 

 the tacts and arguments^ in consequence of which he thinks 

 himself authorized to entertain this opinion. This passage 

 is veiy remarkable, by the opposition discovered in it be- 

 tween the manner in which he and the modern chemists 

 characterize other vegetable products. 



'' Rouellc junior, who examined and carefully compared 

 it with other animal mavters, asserts, that he found it in 

 coloured fecula, and particularly in that called the green 

 fecula of plants. But the expression of fecula, given indif- 

 ferently to the fibrous matter contained in the juice of 

 plants and to starch, having induced chemists to consider the 

 latter as a part of the remains of solid vegetable substances, 

 there is reason to think that it was merely by analogy, 

 and in consequence of some ambiguous properties, that 

 Rouelle was of opinion that the green matter contained 

 gluten. At least the experiments made since that period, 

 and those which I repeated several times on these. coloured 

 feculse, did not confirm this assertion; and nothing has 

 really proved that gluten is one of the principles of the 

 latter tecula." 



" The expression fecula," says Fourcroy, "given wdif- 

 fcrevilij to the fibrous matter contained in the juice of plants 

 and to starch, having induced an opinion that the latter is a 

 part of the remains of solid vegetable substances, there is 

 reason to believe," &:c. 



I shall first observe that this opinion is not correct. For 

 example, chemists at present will never agree w^ith Fourcroy, 

 that the confusion which has been so justly ascribed to the 

 improper use of words has induced those who preceded us 

 to adopt these ideas. Our masters, it must be allowed, 

 gave to things bad denominations j but they did not con- 

 found them more than we do. 



At times even w hen ever)' vegetable deposit was consi- 

 dered by them as fecula, the resemblance of names never 

 deceived them so far as to make them compare starch to 

 the remains of the solid parts of plants. In the first place, 

 we are acqiiainled with no remains of that kind to which 

 chemisls could with reason compare it; and in the se- 

 cond, if any of them took the green fecula for a residuum, 

 there was not one of them who was not perfectly acquamted 

 with the whole diflerence between these fecuhe or remains 

 and starch : and since no confusion of this kind is Ibund 

 '}a their worka^ i^ is not just to reproach them with it ; 



for 



