ON THE PURPLE FOXGLOVE. * 97 
ART. XXIV. — ESSAY ON THE PURPLE FOXGLOVE (DIGI- 
TALIS PURPUREA.) 
By M. Homolle. 
The author commences this treatise, which obtained the 
prize offered by the Societe de Pharmacie, with a general ac- 
count of the several memoirs hitherto published on this sub- 
ject, and then describes some preliminary experiments, previ- 
ously to arriving at the following process for eliminating the 
principle digitaline in a pure and crystalline state. 
2 lbs. of the dried leaves of Digitalis, coarsely powdered 
and previously moistened, are conveyed into a displacement 
apparatus, and treated with water. The mixed liquors ob- 
tained are immediately precipitated with a slight excess of 
subacetate of lead, and thrown on a filter. They pass limpid 
and nearly free from colour, preserving all their bitterness, 
and presenting a slightly acid reaction. Some dissolved car- 
bonate of soda is added until no further precipitate is formed. 
The liquid is filtered anew, and freed from lime which it still 
retains by oxalate of ammonia, and afterwards from salts of 
magnesia by ammoniacal phosphate of soda. 
The filtered liquor presents an alkaline reaction, is clear, of 
a yellow brown tint, and excessively bitter ; a slight excess of 
a solution of tannin is added to it, and the precipitate formed 
collected on a filter and dried between folds of blotting-paper, 
and then mixed whilst still moist with one-fifth of its weight of 
powdered oxide of lead. The soft paste which results is 
thrown on a filter to drain, pressed between blotting-paper, 
and finally dried in a warm chamber. It is then powdered 
and extracted with strong alcohol. 
The alcoholic solution, sufficiently evaporated at a gentle 
heat leaves as residue, in the form of a yellowish granulous 
mass with a small quantity of supernatant mother-ley, the 
9* 
