102 ON THE PURPLE FOXGLOVE. 
Digitaline does not dissolve in phosphoric acid, but merely 
acquires a slightly greenish tint after two or three days. 
In pure concentrated nitric acid digitaline readily dissolves, 
with disengagement of reddish vapours, and forming a beau- 
tiful orange-yellow solution. The following days the solu- 
tion changes to a golden yellow colour, and so remains. 
In all the above reactions the digitaline is more or less im- 
mediately destroyed. 
Acetic acid dissolves digitaline without colouring or chang- 
ing it, at least as quickly as the concentrated mineral acids. 
Action of Potash. — A little potash added to an aqueous 
solution of digitaline causes the bitter flavour to disappear 
slowly; but if the mixture be evaporated to dryness, the bit- 
ter taste gives place to an astringent one. 
The singular property which alkalies possess of destroying 
the bitter taste of certain bodies had already been noticed by 
M. Bouchardat, with respect to synisine and lactacine; but 
we should add, that digitaline, submitted to the action of li- 
quid ammonia for more than 10 days, did not appear to un- 
dergo any alteration. 
We have not found any salt which was ^precipitated by an 
aqueous solution of digitaline. A solution of tannin renders 
the liquor opake white in mass, and opal only if a drop be ex- 
amined ; the precipitate does not begin to form till after 24 
hours. 
Amongst the different properties of digitaline which we 
have passed in review, there is one which seems especially 
characteristic, and which belongs as far as we are aware, to 
no other substance; it is that of forming a beautiful emerald 
green solution with concentrated hydrochloric acid. This re- 
action is the more valuable, as a particle of this substance 
placed in a tube with 2 or 3 drops of hydrochloric acid is suf- 
ficient to develope the green colour after a few instants ; and 
we think that this character ought to form the proper crite- 
rion for discovering digitaline in medico-legal or analytical re- 
