190 
ON THERAPEUTICS. 
instances, and their action being so capable of modification, 
renders them of general utility. 
As stimulants to the skin, or rubefacients, they are valu¬ 
able in all cases where the circulation in the integument is 
defective. Ammoniacal liniments and camphorated spirits, 
aided by friction, are in an especial manner potent in this 
respect, and as they produce no pain nor excitement, are 
available in cases of even acute inflammation. 
As vesicants, or even to the extent of causing suppuration, 
counter-irritants are presumed to be effective in internal in¬ 
flammation. And theoretically the position is true, as they 
cause a diversion of nervous action, and occasion a determi¬ 
nation of blood to the part where they are applied, and in 
this way afford a certain amount of relief to the affected 
organ. Their influence, however, upon the inflamed part we 
rather refer to their action upon the nerves than upon the 
vessels, as we cannot conceive any mechanical interference 
with the circulation in the capillaries of the lungs or intes¬ 
tines to be consequent upon the determination of blood to the 
capillaries of the skin, or a small portion of it; but we can 
understand that an impression upon the nerves of one part 
may moderate, or even destroy, an impression that previously 
existed in the nerves of another. Thus counter-irritations 
applied to the surface diminish internal inflammation, by 
diverting the abnormal excitement to another part of the 
body. Diminished capillary action will naturally follow 
the diminution of the excitement. Practically, however, 
there are two objections to the employment of counter- 
irritants in acute inflammation. 
First, in the acute stage, the agent more frequently than 
not produces no effect upon the skin at all, in consequence 
of the absence of nervous action in the part, as indicated by 
the coldness and insensibility of the surface ; a sufficient 
reason, in our idea, without the necessity for assuming an 
untenable position, to the effect that (C no two diseases of the 
same intensity can exist in the body at the same time.” 
Secondly, when a sufficiently powerful action does result, 
the systemic excitement is so obviously provocative of an 
increase in the activity of the disease, that any benefit re¬ 
sulting from the influence of the agent upon the surface is 
utterly annulled. 
For this, which is by far the principal reason, the best 
practitioners have discontinued counter-irritation in acute 
inflammation. 
In the subacute, or chronic form, the advantages of counter¬ 
irritation cannot well be overrated; no difficulty is expe- 
