INTRODUCTORY LECTURE. 
285 
a principle to do harm, and hence its use became either 
altogether prohibited, or at least it was a matter of accident, 
whether, in particular cases, the good or bad principle might 
prevail in its influence on the system; of such a character is 
opium, so constantly and extensively employed in the practice 
of medicine. It is a matter of general notoriety, that the use 
of opium, in many cases, is utterly precluded, from the 
occurrence in it of two principles, as above described. The 
soothing, calming influence, which it is capable of exercising, 
being, in some constitutions, entirely overruled, and its effects 
counteracted by the stimulating, exciting power, with which 
it is also provided by nature. Pharmacy, by discovering the 
existence of these two principles, and designating the process 
by which they may be separated, has conferred an invaluable 
boon upon the comforts of the sick, and has provided, through 
the skill of the medical practitioner, the means of procuring 
the calm of " nature's sweet restorer," without arousing the 
debilitated nerves of the sufferer into a state of anxious and 
thrilling excitement. There is, perhaps, no more beautiful ex- 
ample of the operations of pharmacy, than the process of sepa- 
rating morphia from opium. This process it will be hereafter 
my duty to describe and explain; at present, a bare allusion to 
it is all that is in my power. 
The separation of quinia from bark, morphia from 
opium, strychnia from nux vomica, and, indeed, of numerous 
other active principles, has led to the introduction of a new 
mode of administering medicines, in which the patient is 
spared the fatigue and nausea attending the ordinary practice 
of swallowing his dose. By a process termed the endermic 
mode, these active principles are introduced into the system, 
and their effects are manifested just as when taken into the 
stomach; according to this mode they are applied either in the 
form of an ointment, or dry powder sprinkled over a small spot 
from which the skin has been removed by the action of a 
blister; and, in some diseases, more success has attended the 
endermic method of treatment than that formerly pursued. It 
enables the action of the medicine to manifest itself directly 
VOL. Ill, — NO. IV. 36 
