COUNTER IRRITATION. 17 



healing by immediate union with those by granulations), we should abstain 

 from applying stimulants {such as blisters, embrocations, and the hot iron) 

 to the seat of injury, until we feel certain that the new vessels in the scar- 

 tissue have become entirely obliterated. 



Muscular waiting is frequently seen in the muscles of parts which have 

 been the seat of inflammation, as in sprain of the shoulder (p. 58) and 

 fracture of the pelvis (p. 503). In the former, the muscles covering the 

 shoulder-blade waste ; in the latter, those of the croup suffer from atrophy. 

 Disuse is the caus.e generally assigned to decrease of substance. ^ I am 

 inclined to tihink that the presence of inflammation, by interfering with the 

 circulation of the part, and conseciuently 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 tihe nervous supply of a part, is a strong factor in the 

 production of atrophy. 



COUNTER IRRITATION.— By this term is understood , the artificial 

 production 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 couniter-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 

 inflammation, which, if that were done, would be aggravated by the soften- 

 ing 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 inflamma- 

 tion, and is on tissues" which will take no hurt from the artificial inflamma- 

 tion 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 fomenta- 

 tions, or friction, to the skin, for the relief of internal congestion or 

 inflammation, aots in t(he same way as a counter-irritant, but less energetic- 

 ally ; the function in both €ases 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. 



MoUer 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 354. 



