ON THERAPEUTICS. 
251 
which had just previously been exalted. This reaction we 
endeavoured to separate altogether from the medicinal action 
which preceded it, by referring to the ordinary occurrence of 
exhaustion after activity, the exhaustion equally following 
excitement of any kind, whether produced by medicinal 
agency or arising from the operation of external causes. 
What we particularly wish to express is, that the depression 
is not the secondary consequence of the medicinal action, 
because we assume all medicinal action to have ceased, but 
the immediate and direct consequence of the excitement which 
the medicine has produced. 
Upon the subsidence of the action of agents of the 
second group we also observe a reaction directly opposed to 
the medicinal effect; a reaction to be explained upon precisely 
the same principles. It is evident that the organ or part 
under the influence of the agents of the second group is in a 
state of rest, or almost absolutely suspended action for a time. 
As soon as the medicinal effect ceases a new activity arises in 
the part, not a consequence of secondary medicinal action, but 
a direct result of the accumulation of force during the period 
of inactivity. 
A careful examination of the effects of the various medi¬ 
cines whose action we are about to consider, will render this 
position perfectly evident. To some, the distinction we are 
endeavouring to make between a direct and secondary result 
may appear unnecessary, as the consequences to the system 
remain the same whether the secondary action be traced to the 
medicine exhibited or to the physiological effect which that 
medicine has produced ; it nevertheless appears to us desirable 
to preserve the distinction rigidly, for the purpose of avoid¬ 
ing the absurdity of calling that a secondary medicinal effect 
which oidy occurs after medicinal action has ceased; further, 
as there are phases of medicinal action belonging to the same 
agent, the expression will commonly mislead. 
Following the plan which we adopted in the first part of 
our essay, of considering each subdivision specially, we pro¬ 
ceed to the discussion of those agents that possess the pecu¬ 
liar property of inducing a condition of c stupefaction ” from 
their direct influence upon the brain and nerves. 
NARCOTICS. 
Although the use of the term “ narcotic” is constant, there 
appears to be some difficulty in defining its precise significa¬ 
tion. According to the ordinary explanation, “ narcotics first 
excite and then depress the nervous functions;” a definition 
which, while it includes a phase of narcotic action, does not 
