00 ON TUB PHYTOLACCA. 



ttfid n c6mpaiative experiment with litmus will corroborate 



this. Into two glasses I put equal quantities of the juibe of 



Phytolacca, which I had turned yellow by a few drops of 



lime water : and into the two otl.er gkisses I put an equal 



weight of infusion of litmus, of an equal depth of colour. 



More than 6o drops of a very weak acid were required to 



redden the infusion of litmus, but less than 15 restored the 



purple colour of the yellow liquor. Hence it follows, that 



the yellow liquor of phytolacca is at least four times as sen- 



tjttt. does not ^ible as the jnfusion of litmus ; but the yellow liquor being 



keep. extremely fugacious, it cannot be kept, or even used but just 



after it is prepared. A few hour^ are sufficient to char.ge it. 



Its spontaneous First a fallow precipitate falls down, which, looked at in the 



changes. ^^^^ exhibits very small scales with the various hues of the 



opal. After a few days brown flocks separate from it. The 



properties of the reagent are then entirely destroyed, and at 



length the liquor is almost wholly deprived of colour. 



The following are the results produced in the purple liquor 



by other reagents. 



Caustic alkalis give it a yellow colour. Alkaline subcar- 



bonijites, a fine violet, that fades, and becomes yellow, by 



Fff cts of re- standing. AVeak atids, nothing perceptible. Dilute oxi- 



apents on the genized muriatic acid, a complete deprivation of colour, with 



purple liquor, ^.j^j^g flocks. Aluiii, uothing apparent on mixing, but after 



some days ^, very light red precipitate. Muriate of lime, no 



change. 31uriate of tin, a red sediment inclining to lil^c, 



and leaving the supernatant fluid colourless. Nitrate of 



lead, a precipitate of the colour of wine-lees. Superoxided 



sulphate of iron, a dirty violet: and on adding au alkali a 



very deep green precipitate, changing yellovv by exposure to 



the air. 



The purple colour that tinges the epidermis of the stalks 



of the Phytolacca is precisely of the same nature as thatcon- 



Tv.. » t •„ tained in the berries, and atlordcd the same results. 

 The colouring 



TuattcTofthe I have convined myself, that this purple does not arise 

 sulks the same. ^j,^jj^^ tiie alteration of any colour by au acid: for having 



chanued it ytdlow by animouia perfectly freed bom carbonic 

 Not a colour "^ ♦ •' . , , : . i i r 



altered by au acid, impregnated hneu with this, and exposed the linen to a 



*^^'^' moderate temperature excluding the air, the purple re- 



appeared in all its lustre as the ammonia was volatilized. 



This 



