44: PHYTOLACCA DECANDRA. 
juice change it to a yellow colour, but the small- 
est quantity of acid is sufficient to restore its pur- 
ple hue. Exposure to the air or large dilu- 
tions is sufficient to restore the original purple. 
-M. Braconnot considers the yellow liquor pro- 
duced by the juice of these berries and lime wa- 
ter as one of the most delicate tests of the pres- 
ence of acid. Into two glasses he put equal 
quantities of the juice made yellow and of an in- 
fusion of litmus of equal depth of colour. More 
than sixty drops of a very weak acid were required 
to redden the infusion of litmus, but less than fit 
teen restored the purple colour of the Phytolacea. 
Hence it follows, that the yellow liquor is four 
times as sensible to the presence of acid, as the 
infusion of litmus. It however requires to be us- 
ed immediately after it is prepared, since a few 
hours cause a spontaneous change in it, which be- 
gins with a precipitate, and ends with a mepeiya- 
tion of colour. — : 
. The effects produced on this —— colour by 
other reagents were as follows. Pure alkalis gave 
it a yellow colour, Alkaline subcarbonates a vio- 
let, that fades and becomes yellow by standing. 
Weak acids no perceptible change. Dilute oxy- 
muriatic acid a complete deprivation of colour 
with white flocculi, Alum nothing at first, but 
