*<J On the Fecula of Green Plants, 



sion, it ought to exhibit other trails of a very striking na- 

 ture before it could be treated as albuminous*. 



It is under this point of" view also that we ought to con- 

 sider the ghiten of fecula, since it is neither tenacious nor 

 elastic, nor susceptible of fermentation like that of wheat f. 

 Rouelle, in announcing it to chemists as a product analo- 

 gous to that of wheat, wished only to exhibit a part of the 

 characters which give them a similarity, those only which 

 belong to the nature of their constituent principles, since ex- 

 ternal characters of resemblance do not exist: my object 

 therefore, in defending the labours of that great master, is 

 much rather to maintain in the catalogue of his discoveries 

 that of an animalized matter found particularly in leaves, 

 than gluten properly so called, because this indeed is the 

 discovery w-hich the author of the System of Chemical 

 Knowledge has rendered problematical in his work. Destroy 

 the aggregation in animalized matters ; deprive silk, horn, 

 wool, feathers, &c. of their form ; it is evident then that, 

 considered in their constituents alone, they will be albumen, 

 gluten, febrine matter, any, every thing you please ; because, 

 if these constituents are every where the same, which has 

 never yet been examined, and what would be the only means 

 to establish the difference between them, would be to fix 

 the proportions according to which nature has united them 

 to give them existence. 



But it may be added. If albumen does not issue from 

 juices with characters so striking as you desire, we must 

 pay attention to the extr.rct, the salts and the acids, which 

 are always found along with it, and which must disguise 

 it a little : it is particularly in the water with which the 

 farina has been washed that you ought to search for it, to 

 find it in that state of purity which will leave no doubt in 

 regard to its nature. Let us see then what the washing of 

 the farina will exhibit. 



* The comparison which Rouelle made of the green juice of plants to 

 an emulsion rests on a much better foundation than he im?ginea. The- 

 cheese separated from the milk of almouds by one of these means, when 

 washe.l and dried, gives oil by expression, and then all the products of 

 caseum by distillation. This no doubt is the reason why almonds and 

 all kinds of nuts give by nitric acid so large a quantity of azote. 



The whey of almonds contains gum, a little extractive matter, and 

 sugar, which is either of the kind obtained from the sugar cane, or of 

 that which I discovered ip grapes, and which 1 shall describe in speak- 

 ing of fermentation. 



f The gluten of wheat is susceptible of a fermentation peculiar to it. 

 The gases thence disengaged in abundance are, the carbonic acid, and 

 hydrogen pretty pure. 



4 JX. Water 



