COUNTER IRRITATION. 17 



part, and consequently with its nutrition, is chiefly to blame ; for in the two 

 cases mentioned, the wasting is local and does not extend to, respectively, 

 the muscles of the forearm or of the second thigh. Interference with the 

 nervous supply of a part, is a strong factor in the production of atrophy. 



COUNTER IRRITATION.— By this term is understood the artificial pro- 

 duction of irritation in one part, so as to relieve the inflammation or to 

 change the diseased action existing in another part. In veterinary practice, 

 the use of counter-irritation is generally limited to stimulating embrocations 

 (liniments), and blisters. The beneficial action of a counter-irritant for the 

 reduction of inflammation, appears to be due to the fact of its producing a 

 flow of exudation into a part in which the presence of this fluid will cause 

 no harm ; the result being that there will be less plasma to escape into the 

 diseased or injured tissues. In such treatment it is evident that the counter- 

 irritant should not be applied on or close to the seat of existing inflamma- 

 tion, which, if that were done, would be aggravated by the softening of 

 the neighbouring tissues. Here, theory and practice prove that it matters 

 little where the counter-irritant is placed, so long as its surface of application 

 is well away from the seat of the previously existing inflammation, and is on 

 tissues which will take no hurt from the artificial inflammation set up in them. 

 Thus, if it be desirable to apply mustard for the relief of inflammation in the 

 lungs, it will be better to rub it over the legs than over the ribs. 



When a blister or similar agent is applied to the seat of inflammation, it 

 may be called a stimulant or irritant ; but cannot, with any show of propriety, 

 be termed a counter-irritant. The application of warm fomentations, or 

 friction, to the skin, for the relief of internal congestion or inflammation, acts 

 in the same way as a counter-irritant, but less energetically ; the function in 

 both cases being to produce anaemia in distant parts. From the foregoing 

 remarks we may see that the popular expression " drawing the blood away 

 from a part," as applied to the action of a counter-irritant, is not incorrect. 



Moller explains that when a blister is applied over a bony enlargement 

 (splint, for instance) in process of formation, it acts by producing pressure on 

 the inflamed tissue (the periosteum, in this case), and thus checks exudation. 



BLEEDING. — Although bloodletting has gone almost as much out of 

 fashion among veterinary surgeons as among doctors, it is a most valuable 

 remedy for relieving a state of abnormally high blood pressure in the arteries, 

 as may occur in pneumonia or in congestion of the lungs. To this object we 

 may safely limit its use. With respect to the character of the pulse in cases 

 of high arterial pressure, see page 356. 



