ON DIGITALIS PURPUREA. 
205 
by the labors of those chemists that have investigated the 
constitution of this important medicine. It is well known to 
all medical readers, that, about fifteen years since, the exist- 
ence of an alkali in this plant was announced by M. Leroyer, 
of Geneva, to which he referred its poisonous qualities. By 
a process, not necessary here to describe, he separated from 
foxglove leaves, a bitter, deliquescent matter, which slowly 
restored the blue color of reddened litmus paper, and which 
Prevost found to be capable of assuming the form of minute 
crystals. To this substance the name of digitaline has been 
given. It possesses the properties of an active poison: a grain 
of it introduced into the abdomen of a rabbit, in a few 
minutes began to retard the respiration and circulation; at 
length the animal, apparently falling into a tranquil sleep, died. 
A solution of half a grain being injected into the circulation 
of a dog, killed him in fifty minutes. 
Thus this substance undoubtedly contains the active prin- 
ciple; but it has been proved that digitaline is neither a proxi- 
mate principle, nor of an alkaline nature, as will appear by 
comparing the experiments of Leroyer, Planiava, Dulong of 
Astafort, Haase, Planizza, Pauguy, Welding, Brault, and 
Poggiole. 
Dr. Graves, of Dublin, was the first who called in question 
the alkaline nature of digitaline, in a paper which he placed 
in my hands a few months after Leroyer's announcement; and 
he showed that when certain precautions are taken, this sub- 
stance does not manifest any alkaline reaction. 
M. Dulong, of Astafort, made an examination of foxglove 
leaves in 1827, which convinced him that they do not con- 
tain a peculiar alkali. He arrived at the following conclu- 
sions: 
1. Digitalis contains a bitter matter, which possesses pecu- 
liar properties, and which ought to be regarded as the active 
principle of the plant. 
2. This matter does not present the characters of vegetable 
salifiable bases. 
