USES OF COUNTER-IRRITANTS 59 



the action of the heart and avert lung congestion, rube- 

 facients, such as soap liniment or mustard paste, are some- 

 times rubbed into the chest, abdomen, or legs, and when the 

 surface is warmed, as it generally will be in ten to fifteen 

 minutes, the dressing is washed off. Counter-irritants are in 

 common use in certain stages of inflammation of the joints, 

 air passages, intestines, and their investing membranes. 

 They are more beneficial in laryngitis and bronchitis affect- 

 ing the larger tubes, and in pleurisy, than in pneumonia. In 

 the outset of inflammatory attacks, by reflex action, they 

 lessen hyperemia, chiefly by stimulating the dilated para- 

 lysed capillaries, thus favouring resolution. In more acute 

 stages, when blood-plasma and red and white corpuscles 

 are escaping through the walls of the distended vessels, 

 fomentations and poultices are generally more suitable than 

 irritants. When the urgency of the febrile' symptoms has 

 somewhat abated, counter-irritants are, however, again 

 useful in promoting absorption of inflammatory products, 

 and they frequently invigorate enfeebled, over-distended 

 capillaries, and substitute higher formative for lower debased 

 action. 



Blisters act more powerfully on horses than on cattle, act 

 uncertainly, and yet require to be used with special caution 

 on dogs, which are apt to bite and rub the blistered parts, 

 and thus induce sloughing. For general purposes in canine 

 practice, iodine is a most useful counter-irritant. The action 

 of turpentine on the skin of horses is peculiar. Applied over 

 a considerable surface, it produces such intense irritation 

 that some animals for a short time become unmanageable, 

 a result the more remarkable as turpentine acts but slightly 

 on the more delicate human skin. 



The choice of a counter-irritant and the mode of using 

 it are determined by various conditions. For prompt but 

 temporary effects, as in combating chill, rousing nervous 

 depression, or overcoming such functional disturbance as 

 occasions colic, mustard and other rubefacients are specially 

 indicated. To act more permanently on parts in which 

 nutrition has been more seriously impaired, cantharides is 

 the appropriate counter-irritant. Where bone, cartilage, or 

 ligament has been chronically affected, still more profound 



