376 ANALYSIS 01 THE HUSKS OF WALNUTS. 



liquid standing on the sediment is a pure and even agreeable 

 acid ; whence it follows, that the acrid and bitter principle 

 has been entirely destroyed, being converted apparently 

 into the black matter approaching the state of charcoal. 

 The same extract gave out no acetous vapour with sulphu- 

 ric acid, even. heated: it contains therefore no acetic acid. 

 A compound From what has been said we cannot but observe in the 



of carbon and husk of the walnut, as in many herbaceous plants, a sub- 



hidiogen dis- 7 J ' ' 



solved in the stance held in solution in its juices; and the hydrocarburet 



juice, as m that ra jj ca i f w hich is more or less decomposable by the simple 

 of many plants. r ™ ; r 



contact of air, which appears to cause a production of 



water, rendering the carbon predominant. It is obviously 

 impossible to have a very accurate idea of a substance so 

 little permanent: but it appears, that it is but slightly co- 

 loured in the vessels of plants; and that the action of the 

 air or of caloric alters it greatly; causing it to pass by de- 

 grees to the state of extract, another principle badly de- 

 fined, of little stability in respect to its element, and which 

 seems rather the result of a decomposition, than a real pro. 

 duct of living nature*. 



Effects of tests The juice of the husk examined by reagents exhibited 

 on the juice. the f l| owing effects . 



Litmus. It strongly reddened infusion of litmus. 



Gelatine. Solution of gelatine formed in it a slight precipitate, 



which must have been owing to tannin. 



Extracts altered * Having had an opportunity of examining some extract of 

 by keeping. rhus toxicodendron, that had been prepared several years before, 

 I made the following observation. I applied some to the skin of 

 an animal, and gave him some internally in pretty large doses, 

 without his experiencing any troublesome consequences; while one 

 drop from the stalk of the plant on the skin occasioned a tolerably 

 extensive inflammation, terminating in an ulcer. Thus it appears, 

 that the principles of plants condensed to the state of extract un- 

 dergo an alteration, which continues progressive with time; and 

 this must cause their action on the animal economy to vary greatly. 

 They should Perhaps apothecaries may prevent this alteration in a certain de^ 



be kept dry, * enc i os i n jr their extracts, when perfectly dry, in vessels 



and air exclud- s .'• J , • °, . , , . r , J J ' 



ej & well stopped ; for the moisture they contain, or have a tendency to 



absorb, does not contribute less to alter the feeble equilibrium of 



Some of their elements, than the contact of air. 



Sulphate 



