ianccer 
A 
Dr Christison on the Umbelliferous Narcotics. 355 
close of June; but an alcoholic extract of six ounces in the begin- 
ning of May killed a rabbit in thirty-seven minutes, when intro- 
duced into the cellular tissue. The leaves are commonly thought 
to be most energetic when the plant is coming into flower in mid- 
summer, and to be very feeble while it is young. The author finds 
it to be probable, that the leaves are very active in midsummer ; 
but he has likewise observed, that they are eminently energetic in 
the young plant, both in the beginning of November, and in the 
month of March before vegetation starts on the approach of genial 
weather. Thirty-three grains of a carefully prepared alcoholic 
extract, representing one ounce and a, third of fresh leaves, killed a 
rabbit in nine minutes, when introduced into the cellular tissue. 
The fruit is most active when it is full grown, but still green and 
juicy. It then yields much more of the active principle conia than 
afterwards when it is ripe and dry. The author added, as a fact 
contrary to general belief, that he had found the ripe seeds of hem- 
lock, and an alcoholic extract of the leaves, to sustain no diminu- 
tion in energy by keeping, at all events for eight years. 
2. Cnanthe crocata, Dead-tongue.—This species is universally 
considered to be the most deadly of all the narcotic Umbellifere. 
Many instances of fatal poisoning with its roots have been published 
during the last two centuries, in the various periodicals of Europe. 
It has repeatedly proved fatal in two hours; and a portion no bigger 
than a walnut has been thought adequate to occasion death. Fatal 
accidents have occurred from it in England, France, Holland, Spain, 
and Corsica. The root would seem from these cases to be the most 
active part ; but few observations are on reecod as to the effects of 
the leaves, and none as to the fruit. The root appears from these 
cases to be very active in all seasons, at least in the beginning of 
January, the end of March, the middle of April, the middle of 
June, and the middle of August. 
The author proceeded to inquire carefully into the effects of season 
upon this species as it grows wild in the neighbourhood of Edin- 
burgh, but was surprised to find that every part of the plant in this 
locality is destitute of narcotic properties at all seasons. The juice 
of a whole pound of the tubers, the part which has proved so deadly 
elsewhere, had no effect when secured in the stomach of a small dog, 
either in the end of October when the tubers are plump and perfect, 
but the plant not above ground, or in the month of June when it 
was coming into flower ; and an alcoholic extract of the leaves, and 
that prepared from the ripe fruit, had no effect whatever when 
introduced into the cellular tissue of a rabbit, under the same con- 
ditions in which the Common Hemlock acts so energetically. By a 
_ comparative experiment he ascertained that tubers, collected near 
Liverpool, where one of the accidents alluded to above happened 
in 1782, act with considerable violence on the dog; and he briefly 
noticed some experiments, made at his request by Dr Pereira, 
