6n vegetable extract. -*4 



« # 



diluted with water, containing the saponaceous principle, 

 was evaporated and redissolred 40 or 50 times on a water- 

 bath. Each time a brown powder, insoluble in water or 

 alcohol, was thrown 1 down. 



The mother water of the infusion of gentian was 

 oxided by oxigen gas, and by oximuriatic acid. The ex- 

 tract from gentian therefore is less greedy of oxigen than 

 that from cinchona, but nevertheless it becomes oxided. 



Though the infusiou of gentian differs from that of cin- 

 chona in not acting on tin or lime, still we cannot say, that 

 it contains a saponaceous principle. 



If extract be insoluble both in pure alcohol and in ether; 

 and the saponaceous principle, or the substance so called, 

 enjoy the same properties ; what are the characteristics of 

 the latter ? 



The root of soapwort was treated in the same manner. Root ^ 

 The infusion comported itself with gelatine and the other wort treated ia 

 reagents, like that of gentian. the same man- 



The saponaceous principle and extract, having the same The same wixfe 

 properties, it should be called therefore, agreeably to the extract. 

 French chemists, extract. 



The matter in coffee announced as a new substance by Principle m 



Chenevix*, and by Paysse as a new acidf , does not differ coffee the 



* J J . ■ same. 



perceptibly fi'om the extract just described. 



Extract then is an immediate principleof vegetables, exist- Properties of 

 ing under various modifications. It combines with several me-* xtract ' 

 tallic oxides, particularly those of tin and iron, and pro- 

 duces a green colour with the latter. It unites also with 

 lime, and with alumine. It always contains nitrogen. 

 When concentrated it exhibits a transparent mass, more 

 or less brown, which attracts the moisture of the air. Very 

 frequently it contains free acetic acid, muriates, and a 

 saccharine matter. 



In living vegetables it appears to be colourless; but 

 oxigen imparts 10 it a black colour. This appears pro- 

 bable from the sap of trees, which is white when it first 

 flows from them. 



It is very probable, that tannin is a modification of extract. Tannin proba- 



• See Journal, vol. II, p. 114. f Ibid, vol, XVII, p. 126- 



It 



