ANESTHETICS. 
19 
The plants which contain pain-allaying principles, used at 
the present day, may he classed as follows : — In the family of 
Solaneee, Atropa belladonna and A. mandragora, Hyoscyamus 
niger (henbane). Datura stramonium, Nicotiana tab a cum ; 
among the Papaveraceae, Papaver somniferum ; in the family 
of Ranunculaceae, Aconitum napellus ; among the Composite, 
Latuca virosa ; in the Scrophularinae, Digitalis purpurea (fox- 
glove) ; and in the Umbelliferae, Conium maculatum, and Cicuta 
virosa. There are others I shall mention presently. 
From all of these, certain active principles, called alkaloids, 
have been extracted. They have all a most remarkable influ- 
ence upon the nervous system, and the alkaloids extracted from 
them constitute some of the most violent poisons with which 
we are acquainted. Some of them have, moreover, a peculiar 
action upon the eye; thus, for instance, Atropa belladonna, 
causes the pupil to dilate in so extraordinary a manner that it 
is not difficult to ascertain that a child has eaten the large 
cherry-like berries of this shrub, when, on approaching a 
lighted candle close to the eye, we find that the pupil does not 
contract as usual. Again, Datura stramonium (Thorn-apple) 
is apt to produce blindness for a time when taken in high 
doses. The calming influence of tobacco ( Nicotiana ) is well 
known ; and headaches cease as if by magic after a short sleep 
induced by eating lettuce {Latuca). Among the mild producers 
of sleep should be mentioned, also, the hop-plant ( Humulus 
lupulus). Pillows stuffed with hops while in flower give repose 
when others, however soft, have not the power of doing so. 
As to opium, the property of the common white poppy 
( Papaver somniferum) , as a soother of pain and a giver of sleep, 
has been known for ages. Opium is the dried juice of the 
seed-vessels of this plant, and derives its name from the Arab 
word Afioum, Its remarkable virtues are almost entirely 
owing to the alkaloid called Morphine, which it contains, to- 
gether with a number of other interesting compounds. 
The Indian hemp {Cannabis indica), which appears to be 
only a variety of our common hemp {C. sativa), possesses 
medical properties very similar to those of opium. Like the 
latter, extract of hemp (known as Haschish) exhilarates, 
intoxicates, induces sleep and anaesthesia,* generally followed by 
headache, nausea, despondency, &c. Hemp was known to the 
Greeks and Romans, but they were ignorant of its remarkable 
narcotic and anaesthetic properties. It was used by the 
Scythians to allay grief and melancholy ; they inhaled the 
fumes given off when the seeds of the plant were thrown upon 
red-hot stones placed upon the ground in the centre of a closed 
* Incapability of feeling pain, &c. 
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