28 On the Fecula of Grccii Plant i. 



*' There exists," says he, " an observation more exact and 

 more positive than that of Rouellc in regard to the presence 

 of this glutinous iTiattcr in the vegetable tissue which forms 

 flax and paper," &cc.*^ To call the author's attention to this 

 passage is sufficient. More details on my part would have 

 too much the appearance of censure. Fourcroy no doubt 

 will suppress it in a new edition, as well as that of the paste 

 of the mallows. If the paste of the mallows had a right 

 to assume a place among the animalized products of ve2;e- 

 tables, we ought to place there also the paste of almonds, 

 paste of eggs, of mannaladc, &c. 



In regard to glue, which is found in the same chapter, 

 every bodv knows that it is merely a kind of turpentine, an 

 iuHammable aromatic resin, soluble in alcohol, which vege- 

 tation forms in the filamentous tissue of the holly; in the 

 fruit of the elder tree, its bark perhaps, and that of other 

 individuals, but under no point of view a glutinous sub- 

 stance. 



X. Potash readily dissolves green fecula and divides it into 

 two parts : one attaches itself to the solvent, and the other 

 separates itself under the form of a gr££n powder which 

 cannot be attacked by new potash. This powder, when 

 wa&hcd and dried, gives by distillation the products of white 

 wood and of flax : that is to say, nothing ammoniacal. 

 This is the ligneous part, which is generally introduced into 

 fecula by trituration. 



This solution has all the characters of an animal solution : 

 it exhales ammonia ; it blackens the silver pan ; and, by the 

 action of acids, emits effluvia which darken traces made by 

 white metals. 



But here, as in soap from wool, a great part of the fecula 

 experiences a degradation which deranges the mode and pro- 

 portion of its radicals. Acids separate from it but very little 

 tecula : the rest assumes an extractive character which dis- 

 poses it to unite with water. Neither -ileohol nor acids can 

 separate this new extract from salts. It is of a fawn colour, 

 and muriate of tin precipitates from it an obscure lake. In 

 regard to the other, when collected and washed on a filter 

 it exhibits this singularity, that it has not lost the property 

 of crisping by the heat of boiling water. 



Alcohol extracts from precipitated fecula a green colour 

 more charged than from that which is fresh. This arises 

 from the resin, which is not destructible like gluten, at- 



Yol, vii. p. 195. 



tachino; 



